Performance requirements and basic types of Medical grade adhesive
For medical device manufacturers, when deciding on an adhesive, extensive testing and verification are often required to determine the performance of the adhesive. This also requires medical adhesives to have special properties to meet the requirements of the medical device market economy and mass production.
The most common medical adhesives have three types of applications:
> Disposables (such as syringes, catheters, oxygenators, etc.)
> Reusable instruments (such as surgical instruments, diagnostic equipment, etc.)
> Implanted devices (such as pacemakers, etc.)
The application of medical adhesive materials not only needs to pass common industry standards (heat resistance, aging resistance, strength, etc.) required by other industrial fields, but also needs to pass toxicity tests or anti-bactericidal tests.
Standards and regulations
Medical devices are related to human health. In the field of medical device manufacturing, people will pay more attention to the selection criteria of adhesives and the requirements for good bonding performance.
The selection of adhesives for medical applications also follows the same process for other applications. Standards include: determination of special bonding substrates, strength requirements, load types, impact resistance, high temperature resistance, low fluid resistance, and processing requirements. However, many medical devices require at least two more important standards: sterilization resistance and low toxicity. The medical device industry has developed several important standards and regulations.
Toxicity and biocompatibility
Adhesives used in medical devices need to be tested for effects on cells (cytotoxicity), blood components (hemolysis), adjacent tissues, and overall biological systems.
Today, adhesive suppliers generally test toxicological properties and biocompatibility according to the following established guidelines:
> United States Pharmacopoeia (USP)-Class VI Standard
> International Standards Organization (ISO)-ISO-10993 (USP Class VI standard)
> ISO-10993 Standard
These standards were originally developed for testing plastics used in medical devices to test contact suitability for possible exposure to body fluids, and now this requirement is also applied to medical adhesives. Generally, products are tested by independent laboratories, and the results are provided to equipment or adhesive manufacturers in a standard certification form. A successful test indicates that the cured product is non-toxic and biocompatible.
It should be noted that another important requirement for medical adhesives is resistance to sterilization. Most disposable and reusable medical devices require sterilization before use.
Some products (such as endoscopes, surgical instruments, etc.) may require multiple sterilization cycles, and the adhesive must withstand these processes without affecting the realization of the main function. Here is information on some common sterilization methods:
Medical device assembly method
Assembly methods for medical device manufacturing include solvent welding, ultrasonic welding, vibration welding, and bonding. Because it does not cause health and safety issues like solvent welding, bonding is widely recognized in the medical device manufacturing industry.
At the same time, bonding does not require expensive equipment investment like ultrasonic or vibration welding. Medical adhesives are highly valued in the medical device assembly industry because they have the following properties:
> Good void filling characteristics
> Can be used for thermosetting and thermoplastic substrates, non-polymer substrates and other different substrates
> Flexible or rigid adjustable
> Uniform stress distribution
> Hermetic seal can be formed between two substrates