How Heat-Resistant Inks Work: Principles and Applications
Date: Jun 05 2025 From: Star Color Views:
Heat-Resistant Ink, also known as "Heat-Resistant Ink", is a special type of ink that can maintain good physical and chemical properties in high-temperature environments without fading, deforming, peeling, etc. Its emergence provides an effective solution to the problem of performance degradation of ordinary inks under high-temperature conditions, and is widely used in the production of various products with strict requirements for high-temperature resistance.
1. What is Heat-Resistant Ink?
Heat-resistant ink refers to a type of ink that forms an ink film with excellent heat resistance, chemical stability, and physical-mechanical properties on the surface of the substrate through crosslinking and curing reactions of components such as resins in the ink by heating or other means.
Heat-resistant inks use special resins and curing systems to undergo crosslinking reactions at high temperatures, forming a three-dimensional network-structured ink film. This structure endows the ink with excellent heat resistance, chemical corrosion resistance, and wear resistance.
Common heat resistance grades of heat-resistant inks include 150°C, 200°C, etc. Different heat resistance grades are suitable for different application scenarios. For example, Zhongzhixing water-based ink does not fade at about 150°C and can be used for food packaging. It can also maintain adhesion even during high-temperature sterilization (120°C).
2. Working Principle of Heat-Resistant Ink
(1) Selection of Resin and Vehicle
Resins and vehicles are key components of heat-resistant inks, and their properties directly determine the heat resistance of the ink. Polyimide has excellent high-temperature resistance, mechanical properties, and chemical stability, and can even be used for a long time in high-temperature environments of 200°C-300°C without easy decomposition or deformation.
(2) Pigment Stability
There is a huge difference in thermal stability between high-temperature resistant pigments and ordinary organic pigments. Ordinary organic pigments are prone to decomposition, sublimation, or color change at high temperatures, leading to color distortion of printed patterns. High-temperature resistant pigments usually use inorganic pigments or specially treated organic pigments, which have high thermal stability and can maintain color stability and vividness in high-temperature environments.
(3) Additives for Improving Heat Resistance
Antioxidants and heat stabilizers are commonly used additives in heat-resistant inks. Antioxidants can inhibit the oxidation reaction of inks with oxygen at high temperatures, preventing ink film aging, discoloration, and performance degradation. Heat stabilizers can improve the thermal stability of resins and pigments, reduce the damage of high temperatures to ink components, and extend the service life of inks.
(4) Crosslinking and Curing Mechanisms
The crosslinking and curing mechanisms of heat-resistant inks are the key to achieving their excellent performance. Common thermosetting reactions include UV + thermal composite curing and thermal crosslinking reactions.
- UV + thermal composite curing combines the advantages of UV curing and thermal curing. First, UV irradiation makes the photoinitiator in the ink generate free radicals, triggering the initial crosslinking reaction of the resin to achieve rapid drying. Then, heating further promotes the crosslinking reaction of the resin, making the ink film fully cured, and improving the hardness, wear resistance, and heat resistance of the ink film.
- Thermal crosslinking reaction is a process in which the resin in the ink reacts chemically with the curing agent through heating to form a three-dimensional network-structured ink film. This curing method can endow the ink with excellent heat resistance and chemical stability.
3. Key Properties of Heat-Resistant Ink
- Wide Temperature Resistance Range: Different types of heat-resistant inks can adapt to environments from 100°C to 300°C or even higher. Within this temperature range, the ink can maintain good physical and chemical properties without obvious deformation, fading, and peeling.
- Color Fastness and Color Retention: These are important performance indicators of heat-resistant inks. High-quality heat-resistant inks can maintain color stability and vividness in high-temperature environments. Even after long-term high-temperature baking or use in high-temperature environments, the color of printed patterns will not change significantly, ensuring the appearance quality of products and the clarity and readability of marks.
- Balance of Adhesion and Flexibility: This is crucial for heat-resistant inks. Good adhesion can make the ink firmly adhere to the surface of the substrate without easy peeling, while appropriate flexibility can ensure that the ink film will not crack when subjected to external forces or temperature changes.
- Antioxidation and Anti-Discoloration Properties: These are also important characteristics of heat-resistant inks. In high-temperature environments, inks are prone to react with oxygen, leading to oxidation, discoloration, and performance degradation of the ink film. Heat-resistant inks can effectively inhibit the occurrence of oxidation reactions and maintain the stability of the ink film and the durability of color by adding antioxidants and adopting special resin and pigment systems.
4. Applications of Heat-Resistant Ink
(1) Electronics Industry
- Cable and Wire Marking: Heat-resistant inks are indispensable for cable and wire marking. During the production and use of cables and wires, they may be affected by factors such as high temperature and friction. Ordinary inks are easy to peel off or fade, resulting in blurred marks. With excellent adhesion and heat resistance, heat-resistant inks can form firm and clear marks on the surface of cables and wires, facilitating the identification and use of cables and wires.
(2) Automotive and Aerospace
- Engine Parts and Exhaust Systems: In the automotive and aerospace fields, parts such as engine components and exhaust systems work in high-temperature environments, and the requirements for the heat resistance and wear resistance of marking inks are extremely strict. Heat-resistant inks are used for marking printing in these parts, which can maintain the integrity and clarity of marks under harsh conditions such as high temperature, high-speed airflow, and mechanical vibration.
- High-Temperature Sensor Labels: High-temperature sensors in automotive and aerospace equipment are used to monitor key parameters such as temperature, and their labels also require heat-resistant inks.
(3) Packaging and Labeling
- Cooking Bags, Microwave Food Packaging, and Heat-Seal Bags: In the field of packaging and labeling, heat-resistant inks are widely used in products such as cooking bags, microwave food packaging, and heat-seal bags. Cooking bags and microwave food packaging need to withstand high-temperature cooking or microwave heating during use. Ordinary inks are easy to melt and migrate at high temperatures, causing pollution to food. Heat-resistant inks have good high-temperature resistance and chemical stability, which can remain stable in high-temperature environments and ensure the safety and aesthetics of packaging.
With its excellent high-temperature resistance, outstanding color fastness, good balance of adhesion and flexibility, and excellent anti-oxidation and anti-discoloration capabilities, heat-resistant ink plays an irreplaceable role in many key fields such as electronics, automotive, and packaging.
With the rapid development of science and technology and the continuous upgrading of industry needs, heat-resistant inks have great future development potential.
- With the increasing strictness of environmental protection regulations, the development of more environmentally friendly heat-resistant inks with low VOC (volatile organic compounds) will become an important trend.
- On the other hand, driven by intelligent and precision manufacturing, heat-resistant inks are expected to expand their application boundaries in emerging fields such as nanoscale printing and intelligent sensor integration, bringing more innovations and possibilities to industrial production and daily life.
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