Medical injection molding is a critical process in the manufacturing of medical devices, where material selection directly impacts the safety, reliability, and effectiveness of the devices. In the medical field, material selection must not only consider the functionality of the product but also meet stringent requirements for biocompatibility, chemical stability, and processability.

1. Biocompatibility: The Primary Standard for Material Selection

Biocompatibility is the foremost criterion for selecting materials in medical injection molding. Materials must pass biocompatibility tests, such as ISO 10993, to ensure they do not cause toxic, allergic, or irritant reactions when in contact with human tissues or blood. Commonly used biocompatible materials include medical-grade polycarbonate (PC), polypropylene (PP), and polyether ether ketone (PEEK). These materials undergo rigorous testing and certification to meet the demands of both long-term implants and short-term contact medical applications.

2. Chemical Stability: Key to Ensuring Medical Safety

Medical injection molding materials must exhibit excellent chemical stability, enabling them to withstand various sterilization methods such as high-temperature steam sterilization, ethylene oxide sterilization, and gamma radiation. The materials must not degrade, discolor, or lose performance during sterilization. Additionally, they must resist erosion from chemicals like drugs and bodily fluids to maintain long-term stability. For example, polytetrafluoroethylene (PTFE) is widely used in medical components requiring high chemical stability due to its exceptional chemical inertness.

3. Processability and Functionality: Meeting Complex Medical Needs

Medical injection molding materials must possess good processability to meet the complex structural requirements of precision medical devices. Processing characteristics such as flowability, shrinkage rate, and thermal stability must align with product design and mold manufacturing processes. Furthermore, the materials must fulfill specific functional requirements, such as transparency, strength, and wear resistance.