One Production Line, Three Challenges: AutoRICH’s Integrated Solution for PI Film Production

Polyimide (PI) film is widely used in fields such as flexible displays, semiconductors, and new energy. For PI material manufacturers, progress in formulation R&D does not necessarily mean the process is ready for scaled-up production. Whether polymerization remains stable, whether the material state before film formation can be effectively controlled, and whether the synthesis and casting steps connect smoothly all affect final production performance.

These issues are often interrelated. Changes in molecular weight and viscosity in the PAA (polyamic acid) system affect downstream conveying and coating; bubbles, particles, and metallic impurities can cause film-surface defects; and mismatched equipment conditions and control parameters between upstream and downstream processes add difficulty to pilot-plant scale-up and continuous production commissioning.

If polymerization, degassing, conveying, and casting equipment are selected separately and commissioned independently, the fact that each individual machine runs normally does not mean the combined process will run stably. The problem may lie at equipment interfaces, or in a mismatch between the material state and downstream processes.

AutoRICH brings the PI synthesis reaction system and the precision casting line into an integrated solution design. Centering on material characteristics, process control, and process connection, it coordinates dosing, polymerization, dispersion, degassing, conveying, coating, and drying. The focus is not just on which equipment to configure, but on ensuring that the operating conditions of each step can match one another.

Challenge 1: Whether polymerization remains stable depends on process control of the PAA system

The key upstream step in PI production is PAA synthesis. The stoichiometric ratio of dianhydride and diamine monomers, the dosing state, reaction temperature, and mixing conditions all influence the polymerization process, and thereby affect PAA’s molecular weight, viscosity, and system uniformity.

These variations propagate downstream. Fluctuations in PAA viscosity may change the material’s conveying and discharge behavior, and also increase the difficulty of adjusting casting/coating conditions. Therefore, polymerization equipment needs to integrate dosing metering, reaction-condition control, and system-state monitoring — not just accomplish material mixing and reaction.

AutoRICH’s complete PI synthesis reaction equipment is designed around metering of powder and liquid materials, enclosed reaction, and process monitoring. Precise metering is used to control the monomer ratio and dosing process; inert-gas enclosed protection is used to reduce the influence of the external environment on the reaction system; temperature control and online viscosity monitoring provide a basis for tracking the reaction process and judging the system state. For modified PI and blended systems containing nanofillers, AutoRICH’s self-developed dispersion and homogenization units are used to improve the dispersion state of the material and reduce the impact of local agglomeration on system uniformity.

These designs correspond to different process requirements: metering controls dosing conditions, temperature control acts on the reaction process, online monitoring helps identify system changes, and dispersion/homogenization addresses dispersion issues in mixed systems. Their combined effect is to supply PAA material of a relatively stable state to downstream conveying and casting, reducing process adjustments caused by upstream system fluctuations.

Challenge 2: Bubbles, particles, and metallic impurities need to be controlled separately before film formation

Before PAA enters the casting process, bubbles entrained in the material, gel particles, and metallic impurities are all factors that need attention.

PAA has a certain viscosity, and bubbles introduced during mixing and conveying may not escape on their own; particles, gel, and metallic impurities that may be introduced through equipment contact also increase the difficulty of film-surface quality control. These factors may be related to defects such as pinholes and specks, with a particularly significant impact on PI film production that demands high cleanliness.

Different types of defects have different sources and cannot all be resolved by a single filtration pass or a single degassing treatment. Particle filtration, metallic-impurity control, and bubble removal each need to be designed according to their own target, and coordinated with the material conveying method.

AutoRICH incorporates enclosed conveying, multi-stage filtration for impurity removal, and vacuum degassing into the whole-line solution.

From the reaction system outlet to the casting die, enclosed conveying reduces the risk of contamination from material exposure and multiple transfers. Multi-stage filtration and iron-removal measures target particles within the corresponding filtration ranges and the metallic impurities that can be handled by the iron-removal unit, respectively. Vacuum degassing reduces the bubble content in the system, thereby reducing the risk that bubbles entering the casting step cause film-surface defects.

The three types of measures each play a role. Filtration targets particles that can be retained, iron-removal focuses on the corresponding metallic impurities, and vacuum degassing is responsible for reducing entrained gas. Enclosed conveying runs throughout the material-transfer process, providing a relatively continuous material path for these treatment steps.

Incorporating the above units into a unified whole-line design helps reduce repeated transfers and control the material state before casting. For products such as CPI (colorless transparent PI) and electronic-grade PI, the cleanliness-control scheme also needs to be determined in combination with the material system, wetted-part configuration, and product requirements.

Challenge 3: How synthesis and casting connect — process scale-up requires additional high-precision commissioning

Being able to prepare material that meets expectations in the laboratory does not mean the same process can be used directly for pilot or scaled-up production. When the synthesis equipment and casting line are supplied by different vendors, piping interfaces, material conveying, and control systems often need to be coordinated separately. PAA’s viscosity and conveying state affect casting conditions, and coating and drying processes also need to match each other. If the upstream and downstream equipment lack a unified design and control logic, process scale-up may require repeated parameter adjustments and re-verification of the compatibility between pieces of equipment.

Equipment being connectable does not mean the process is connected. Whole-line design needs to consider the material conditions and operating requirements between upstream and downstream processes at the equipment selection and layout stage. AutoRICH integrates the synthesis unit and the precision PI casting line in a unified design, and uses a unified DCS digital central control, key-parameter monitoring and interlocking control, and continuous enclosed conveying to reduce control fragmentation and process-adaptation work between different equipment.

In the casting step, a precision coating die is used to control the coating process. The drying oven adopts sectioned, gradient temperature control, organizing heat input according to the requirements of each drying stage so that solvent evaporation and film-layer formation coordinate with each other. Compared with a uniform temperature setting, sectioned temperature control makes it easier to adjust drying conditions for different stages, reducing the risk of mismatch between the drying process and the material state. Continuous operation also involves tension and steel-belt position control. Closed-loop tension control adjusts tension according to operating state, and steel-belt edge-guiding is used to control the running position of the belt. Together with coating and drying conditions, these help reduce the impact of operating fluctuations on the film-forming process.

The practical significance of these designs is to bring matters that would otherwise require cross-equipment coordination into a single engineering solution as much as possible. Unified interfaces, control, and integration thinking help reduce repeated commissioning and make process development, equipment joint commissioning, and production introduction connect more smoothly.

From laboratory bench-scale to pilot, and then to scaled-up production, formulation, equipment specifications, and operating conditions still need corresponding validation. Integrated design can provide a more consistent equipment base for different stages and reduce the complexity caused by equipment differences and process connection during process migration — but it cannot replace specific process validation.

One Production Line — the Key Is Designing the Relationships Between Processes Clearly

PI film production involves monomer dosing, polymerization reaction, dispersion/homogenization, degassing and purification, enclosed conveying, casting/coating, sectioned gradient drying, and downstream imidization support and winding. Each step does not run independently: the material state formed upstream affects downstream process conditions, and the operating states of coating and drying also need to match.

Around this process chain, AutoRICH coordinates the key equipment, material conveying paths, process control, and upstream-downstream process interfaces, and includes equipment joint commissioning, process development, installation and delivery, and ongoing after-sales maintenance in the overall project implementation. This reduces the coordination work caused by segmented equipment procurement and independent commissioning, and lets process requirements be implemented earlier in equipment design and system integration.

AutoRICH’s integrated PI production line has been put into operation in projects of leading domestic new-material customers. For different material systems and production needs, the whole-line solution needs to be designed and validated in combination with formulation characteristics, process routes, and production-line configuration.

From formulation development to stable production, equipment selection is only one part. Whether a matching process chain can be formed among polymerization, material handling, and casting also determines the implementation and operating results of the production line.

AutoRICH provides full-process PI process equipment solutions. We welcome raw-material trial runs and production-line solution discussions to jointly explore equipment configurations suited to specific material systems and production needs.