Nickel plated copper foil (PI film) and tin plated copper foil (PI film) are high-performance thin film insulation materials

Overview of PI membrane

The first time you hear about PI polyimide film, you may not know what it is, but those who are familiar with PI film know that it is also called polyimide film. Its main component is polyimide, which is a high temperature resistant and highly stable thin film. Polyimide film is widely used in the field of electronics, and its color is usually brown or black. People who have a certain understanding of hot melt adhesive film will consider using hot melt adhesive film as PI film. What are the types of hot melt adhesive films used for polyimide film and PI film?

There are mainly two types of hot melt adhesive films used for PI film bonding: PA and PES. Because the hot melt adhesive films of PA and PES have some common characteristics with polyimide PI film, the adhesive force is strong and the effect is good during bonding. Let's analyze it in detail below.

The main component of polyamide hot melt adhesive film is copolyamide, which has a certain common relationship with polyimide film in terms of composition. Therefore, when using polyamide hot melt adhesive film to bond polyimide film, its viscosity is very good, and the melting point of polyamide hot melt adhesive film is very high, generally 115-130 ℃, belonging to high temperature type. The recommended use temperature is 140-160 ℃, and it still has good viscosity and stability at high temperatures, which is also in line with the characteristics of the application field of polyamide adhesive film.

The main component of polyester hot melt adhesive film is copolyester, which has good viscosity to PI film. The biggest feature of polyester hot melt adhesive film is its excellent washing resistance, which can maintain good adhesion even when in contact with water, and has relatively low cost. However, its adhesion performance is slightly worse than that of polyamide hot melt adhesive film.

Basic concepts

Polyimide (PI) is an aromatic heterocyclic polymer compound containing acyl groups (- CO-NH-CO -) in the main chain of the molecule. It is mainly divided into three categories: thermoplastic polyimide, thermosetting polyimide, and modified polyimide.

• Thermoplastic PI includes homopolymer type, biphenyl type, ether anhydride type, fluoroanhydride type, etc;
• Thermosetting PIs include bismaleimide, acetylene terminated polyimide, norbornene dianhydride terminated polyimide, etc;
• Modified PI includes polyetherimide, polyesterimide, etc.

The PI film is yellow transparent with a relative density between 1.39-1.45.

performance

PI is currently the most heat-resistant polymer material that can be practically applied, and it can maintain good performance at low temperatures without deformation in the range of -269 ℃ to 280 ℃ for a long time. In addition, PI materials have good performance in processing performance, mechanical performance, insulation performance, flame retardancy, chemical corrosion resistance, radiation resistance, and many other aspects.

PI film has superior performance and a wide range of downstream applications

PI film has superior performance and a wide range of downstream applications. The product forms of polyimide include film, foam, fiber, photosensitive polyimide and polyimide based composites, among which PI film accounts for more than 70%, which is the most important product form of polyimide industry. The manufacturing of PI film requires production processes such as resin polymerization, cast sheet, directional stretching imidization, and post-treatment. The product has excellent characteristics such as high heat resistance, strong mechanical properties, low dielectric constant, and low expansion coefficient, and is known as the golden film. It is widely used in high-tech industries such as consumer electronics, high-speed rail, wind power, aerospace, and flexible displays downstream.

Polyimide film, also known as PI film, is the world's best performing thin film insulation material. It is composed of phthalic anhydride (PMDA) and diaminodiphenyl ether (DDE) condensed and cast into a film in a strongly polar solvent, and then imidized. Polyimides can be classified into two types based on their chemical composition: aromatic polyimides and aliphatic polyimides; But it is mainly classified based on processing characteristics, divided into thermoplastic polyimide and thermosetting polyimide. Among them, thermoplastic polyimides are mainly used in imine films, coatings, fibers, and modern microelectronic polyimides, while thermosetting polyimides mainly include bismaleimide (BMI) type and monomer reactant polymerization (PMR) type polyimides and their respective modified products.

Due to the presence of an imide ring (- CO-NH-CO -) on the main chain of polyimide (PI), it is a type of polymer with a highly stable molecular structure, high modulus, high strength, high and low temperature resistance, lightweight, flame retardant, and other characteristics. In addition, polyimide also has characteristics such as low temperature resistance, low coefficient of expansion, flame retardancy, and good biocompatibility.

Whether using polyamide hot melt film or PES hot melt film to bond PI film, they are both environmentally friendly adhesives that are solid at room temperature and have adhesive strength only after melting into a liquid state at a certain temperature. Due to these two characteristics, they can be conveniently stored and transported at room temperature, and the operation process is simple and the processing speed is fast, greatly improving the efficiency of bonding composite systems.

Overall, there are two types of hot melt adhesive films suitable for polyimide film PI: PA and PES. In addition, using hot melt adhesive film to bond polyimide film PI has great advantages, which can reduce costs, improve work efficiency and bonding effect. Therefore, more and more people choose to use hot melt adhesive film to composite polyimide film PI film.