Thermoplastic Polyimide TPI

Thermoplastic polyimide (TPI) is developed on the basis of traditional thermosetting PI. Compared with thermosetting PI, TPI has many potential advantages.

1. TPI has the advantages of excellent processing performance, toughness and damage resistance, short production cycle, simple operation and low manufacturing cost.

2. TPI can be melted and reprocessed, so damaged structures can be repaired by applying heat and pressure.

3. TPI has the advantage of being environmentally friendly. It is a fully imidized polymer and does not contain reactive chemicals, so its toxicity is very low.

 TPI processing technology

There are three common processes for the processing of thermoplastic polymers: injection molding, compression molding, and extrusion.

1) Injection molding process

Injection molding refers to the process of injecting heated and melted materials into a mold, cooling and solidifying them to obtain a molded product. It is also called injection molding and is suitable for mass production and complex-shaped products.

Advantages of injection molding process:

A. Less waste loss.

B. There is no need to further improve the parts after molding.

C. Short molding cycle.

Disadvantages of injection molding process:

A. Parts must be designed according to specific molding requirements.

B. There may be fusion seams on injection molded parts.

C. Products with thicker walls cannot be injection molded as shrinkage holes are likely to occur.

D. It is suitable for products with large batches. Products with small batches will result in greater waste.

The injection molding process of thermoplastic polyimide (TPI) is relatively mature, but it still has major limitations. For example, it is not suitable for injection molding of large parts. The shrinkage holes after injection molding will significantly affect the use of the product.

2) Compression molding process

In compression molding, a certain amount of plastic (which can be powder, granular or flake, etc.) that is usually preheated is placed in a heated mold cavity, and then the mold is closed and pressure is applied to the plastic to melt it into a viscous flow state and fill the mold cavity to form a product; after the product solidifies, the mold is opened and the product is taken out.

Advantages of compression molding:

A. The internal stress of the product is very low, the warping deformation is also very small, and the mechanical properties are relatively stable.

B. The wear of the mold cavity is very small and the maintenance cost of the mold is low.

C. It can form relatively large flat products. The size of the products that can be formed by molding is only determined by the clamping force of the existing molding machine and the size of the mold plate.

Disadvantages of compression molding:

A. The molding cycle in the entire production process is long, the efficiency is low, and it consumes a lot of physical energy for the workers.

B. Compression molding is not suitable for complex products with depressions, side slopes or small holes.

C. This process has some shortcomings for products with very high dimensional accuracy requirements (especially for multi-cavity molds).

Thermoplastic polyimide (TPI) compression molding process is relatively mature and more suitable for making some thick-walled plates, which are then machined into the required parts. This process is basically used more in the market to produce TPI plates, but its molding cycle is long and the low efficiency of the processing method leads to slow batch production and high processing costs. In addition, the compression molding method cannot guarantee the yield of bars and pipes, which relatively increases the cost of use for customers.

3) Extrusion molding process

Extrusion molding is also called extrusion, extrusion, and extrusion molding. It is a process that uses the extrusion effect of the screw and the plunger to force the uniformly plasticized plastic through the die to become a continuous product with a constant cross-section.

Advantages of extrusion molding:

A. The equipment is easy to manufacture and has low cost.

B. It can be produced continuously with high production efficiency.

C. The equipment has a high degree of automation and low labor intensity.

D. The production operation is simple and the process control is easy.

E. Extruded products are uniform, dense and of high quality.

Disadvantages of extrusion molding:

A. Three-dimensional products cannot be produced.

B. The cost of raw materials required for startup is relatively high, often requiring dozens or even hundreds of kilograms for one startup.

The extrusion molding process of thermoplastic polyimide (TPI) is relatively immature. Due to the poor thermal stability of thermoplastic PI, easy degradation and hydrolysis, and severe die swelling effect, the continuous extrusion production of thermoplastic polyimide (TPI) is directly affected, resulting in almost no domestic manufacturers being able to achieve continuous extrusion molding of polyimide (PI) profiles. TPI requires relatively strict processing conditions during extrusion, and the processing window of extrusion temperature, molding pressure, etc. is relatively narrow. The extrusion molding process can greatly shorten the molding cycle, and continuous production can ensure product consistency and good stability.

After a long period of exploration, Jiangsu Junhua Special Engineering Plastic Products Co., Ltd. has been able to maturely and stably extrude thermoplastic polyimide (TPI) profiles continuously.

 Industrial Application of TPI 

Mechanical industry: TPI has excellent mechanical properties and friction resistance, and can replace titanium alloys to manufacture various parts, such as engine inner covers, dense parts, clutch gear rings, etc.

Aerospace: TPI has good flame retardant properties and can reduce damage to aircraft caused by fire.

Electronic Communications: TPI can maintain good electrical insulation in harsh working environments such as high temperature, high pressure and high humidity. It is usually used to manufacture wafer carriers, electronic insulating films and various connected equipment.

Medical: Artificial bones made of TPI resin are lightweight, non-toxic and highly corrosion-resistant.

Electricity: TPI has good thermal stability and dielectric properties and can be used to produce various electrical equipment such as wires and cables.

Coating: Covering the metal surface with TPI fine powder coating can obtain TPI powder metal coating products with excellent insulation, strong corrosion resistance, heat resistance and water resistance. They are widely used in chemical corrosion protection, household appliances, electronic products, machinery and other fields.

 Junhua PEEK

Junhua PEEK has been committed to the research, development, production and sales of high-performance special engineering plastics such as PEEK and PI for 16 years. It has rich experience in collaborative research and development, sample testing, batch production, technical support and after-sales service guarantee. We look forward to using our knowledge and capabilities to provide you with long-term application solutions in various application fields such as PEEK and PI.