What are the requirements for medical injection molding materials?
With the rapid development of the medical device industry, medical injection-molded parts—valued for their high precision, low cost, and ability to create complex structures—are widely used in disposable syringes, catheters, surgical instrument housings, and other applications. To ensure the safety and reliability of final products, medical injection molding materials must meet a series of stringent requirements:
1. Biocompatibility
When in contact with human tissues or bodily fluids, materials must not trigger immune responses, inflammation, or toxic effects.
Common materials: Medical-grade polypropylene (PP), polystyrene (PS), polycarbonate (PC), polyether ether ketone (PEEK), etc., all requiring compliance with ISO 10993 series biological evaluations.
2. Chemical and Physical Stability
Chemical resistance: Must withstand immersion in and cleaning with common disinfectants without degradation or surface damage.
Aging resistance: Maintain stable performance under prolonged exposure to UV light and thermal-oxidative environments without becoming brittle.
3. High-Temperature and Sterilization Resistance
Must endure common sterilization methods: high-temperature steam (above 121°C), ethylene oxide (EO), gamma radiation, etc.
No thermal deformation or performance degradation post-sterilization to ensure safe, aseptic use.
4. Mechanical Properties
Sufficient tensile strength, impact resistance, and hardness to meet mechanical demands in scenarios like injections and infusions.
Flexibility or rigidity tailored to specific applications, such as disposable catheters or housings.
5. Processing Performance
Excellent melt flow and mold-filling capabilities for intricate structures and thin-walled designs.
Stable shrinkage rates and high dimensional accuracy to avoid post-processing or rework.
6. Non-Toxicity, Odorlessness, and Cleanliness
Raw materials must be free of harmful substances, such as plasticizers, heavy metals, or residual organic solvents, that could leach into the human body.
Smooth surfaces free of bubbles and cracks to meet the cleanliness standards of medical-grade sterile packaging.
