In blister packaging products, PET precision parts packaging trays serve as core load-bearing components, and their chemical corrosion resistance directly impacts the storage safety and lifespan of the parts. In high-precision fields such as pharmaceuticals and electronics, trays are in prolonged contact with chemicals such as cleaning agents, lubricants, and acid/alkali solutions. Insufficient material corrosion resistance can easily lead to surface swelling, cracking, and even the release of harmful substances that contaminate the parts. Therefore, improving the chemical corrosion resistance of PET trays requires a multi-dimensional approach, encompassing material modification, surface treatment, structural design, and process optimization.
Material modification is fundamental to improving corrosion resistance. Traditional PET molecular chains contain ester bonds, which are easily attacked and hydrolyzed by alkalis, leading to a decline in material performance. Introducing corrosion-resistant monomers through copolymerization modification, such as isophthalic acid (IPA) replacing part of terephthalic acid, can reduce ester bond density and enhance the chemical stability of the molecular chain. Furthermore, adding inorganic fillers such as nano-silica or silicon carbide can form a dense barrier within the PET matrix, hindering the penetration of chemical substances. These fillers can also suppress crack propagation by dispersing stress concentration points, further improving the pallet's impact resistance and extending its service life in corrosive environments.
Surface treatment technology is key to directly blocking chemicals. Plasma surface treatment introduces oxygen-containing functional groups (such as hydroxyl and carboxyl groups) into the PET surface through high-energy particle bombardment, increasing the surface energy to over 55 mN/m and enhancing the adhesion of inks or coatings. Based on this, coating with fluoropolymers (such as polytetrafluoroethylene) or silane coupling agents can form a nano-scale hydrophobic and oleophobic layer, effectively reducing the adsorption and penetration of chemicals. For pallets exposed to highly corrosive environments for extended periods, physical vapor deposition (PVD) technology can be used to deposit diamond-like carbon (DLC) films, which have a hardness approaching that of natural diamond and are extremely chemically inert, resisting the corrosion of most acid and alkali solutions.
Optimized structural design can reduce the retention of chemicals on the pallet surface. Avoiding right-angle transitions or flat structures and instead using rounded corners and streamlined grooves reduces cleaning difficulty and chemical residue. Incorporating drainage channels or an angled design at the bottom of the pallet accelerates liquid dispersion and prevents localized accumulation that can lead to corrosion. For precision parts, a layered structure can be designed, with the upper layer using a highly corrosion-resistant material (such as PETG) and the lower layer using low-cost PET, ensuring protection in critical areas while controlling overall costs. Furthermore, increasing the pallet wall thickness can improve its resistance to swelling, but a balance must be struck between material usage and lightweight requirements.
Manufacturing process control has a decisive impact on the pallet's corrosion resistance. During injection molding, strict control of melt temperature and injection pressure is crucial to prevent overheating and decomposition of the material, which produces low-molecular-weight substances that can form micropores and become the starting point for chemical corrosion. Using high-precision molds and slow cooling processes reduces residual stress within the pallet, lowering the risk of stress corrosion cracking. In post-processing, annealing eliminates internal stress generated during molding, increases material crystallinity, and further enhances chemical resistance. For pallets requiring printed markings, corrosion-resistant inks should be selected, and printing should be avoided in grooves or edge areas to prevent ink peeling and localized corrosion.
Environmentally adaptable design is an important means of ensuring the long-term performance of pallets. Customized pallets can be designed for different chemical environments. For example, pallets used in strong acid environments can be filled with zirconium oxide or alumina fillers to improve their acid resistance; in chlorine-containing environments, carbon-containing fillers should be avoided to prevent chloride ion-induced stress corrosion. Furthermore, accelerated aging tests simulating real-world usage scenarios can assess the lifespan of pallets in specific chemical environments, providing a basis for design optimization. For instance, immersing pallets in a 5% sodium hydroxide solution and regularly monitoring their mass changes and mechanical property degradation can quickly screen for material formulations with excellent corrosion resistance.
Long-term performance monitoring and maintenance are the last line of defense to ensure stable pallet quality. Establishing pallet usage records, documenting the types, concentrations, and exposure times of chemicals they come into contact with, allows for prediction of their remaining lifespan and timely replacement of aging pallets. For reusable pallets, thorough cleaning is required after each use to prevent cross-corrosion caused by chemical residues. Regularly using infrared spectroscopy or scanning electron microscopy to examine changes in the microstructure of the pallet surface can detect defects such as swelling and cracks early, preventing problems from escalating.
Improving the chemical resistance of PET precision parts packaging trays in blister packaging products requires a comprehensive approach throughout the entire material lifecycle, including design, manufacturing, use, and maintenance. Through integrated measures such as copolymer modification, surface coating, structural optimization, process control, and environmentally adaptable design, the service life of the trays in corrosive environments can be significantly extended, ensuring the safe storage of precision parts and providing reliable quality assurance for high-precision industries such as pharmaceuticals and electronics.
