How is polyimide film heat-sealed?

Polyimide Film
Polyimide film (PI film) is one of the organic polymer materials with the best comprehensive performance, offering numerous exceptional characteristics:

• Thermal Resistance: Long-term operating temperature ranges from -200°C to 300°C, with no distinct melting point observed in some variants, and the ability to withstand temperatures exceeding 400°C.
• Mechanical Properties: Tensile strength of 200 MPa at 20°C and over 100 MPa at 200°C, combined with high elastic modulus (e.g., Upilex S achieves 400 MPa).
• Insulation: Dielectric constant <3.5, volume resistivity of 10&sup1;⁷ Ω·cm, and excellent corona resistance.
• Chemical Stability: Resistant to strong acids, alkalis, organic solvents, and radiation (retaining 86% strength after 5×10⁹ rad exposure).
• Lightweight and Flame Retardant: Density ranges from 1.39 to 1.45 g/cm&sup3;, with a UL-94 flame retardant rating of V-0.

Heat Sealing Machine
A heat sealing machine utilizes a high-frequency electromagnetic field to induce molecular collisions within materials, generating heat for purposes such as fusion or embossing. Below are its working principles and features:

Working Principle:
A high-frequency heat sealer generates a high-frequency electromagnetic field through an electron tube self-excited oscillator. The object to be processed is placed between the upper and lower electrodes. The material’s internal molecules vibrate rapidly under the electromagnetic field, producing friction-induced heat to achieve fusion or embossing. High-frequency heating relies on electromagnetic field oscillations at frequencies ranging from tens of thousands to hundreds of millions of cycles per second. It can be categorized into high-frequency induction heating, dielectric heating, plasma heating, and microwave heating. Dielectric heating, known for its speed, uniformity, and efficiency, is widely used in modern industries. In plastic packaging, high-frequency dielectric heating is applied via heat sealers (welding machines), which convert alternating current to direct current and then to high-frequency power for processing.

Features:

• Temperature Control: Shanghai Puxiong’s ultra-high-temperature film heat sealer can reach temperatures exceeding 400°C, meeting the sealing demands of polyimide films and other high-temperature materials.
• Versatility: Suitable for sealing plastics, films, and more. Applications include membrane structure welding in construction and sealing of medical products like disposable blood transfusion bags and urinary catheter bags.

Integrated Applications of Polyimide Film and Heat Sealing Machines
Owing to its outstanding properties, polyimide film is widely used in high-tech sectors such as aerospace, electronics, and new energy. In these fields, heat sealing is often required to bond polyimide films with other materials or form specific structures. For example:

• In aerospace, polyimide films are used for rocket thermal barriers and spacecraft structural materials. Heat sealers ensure airtight sealing and structural stability when bonding polyimide films to other components.
• In electronics, heat sealing enables precise integration of polyimide films into circuits or insulation layers.
• In new energy, the combination supports durable sealing for battery components and flexible solar panels.

This synergy between advanced materials and precision machinery drives innovation across cutting-edge industries.