Sterilizable and autoclavable plastics

The deliberate sterilization of devices and components made of plastic is designed to destroy as many living microorganisms such as bacteria, viruses, algae and their spores as possible. There are several methods for sterilization of plastics. Depending on the sterilization process used, some materials are more suitable than others.

Steam autoclavable plastics

In accordance with DIN EN 285, all surfaces of the objects being sterilized must be exposed to pure saturated water vapor at 273.2°F for at least three minutes. Steam sterilization or autoclaving is regarded as the safest and cheapest of all the sterilization methods. However, the high process temperatures involved makes it less suitable for materials sensitive to heat and hydrolysis.

  • PEEK medical grade
    TECAPEEK MT shows no significant loss of mechanical properties, even at more than 1,500 sterilization cycles. Also, further negative influences like discoloration or color change (yellowing), or even calcification are not seen above 1,500 cycles.
  • PPSU medical grade
    TECASON P MT shows no significant loss of mechanical properties until 800 sterilization cycles. Also, significant discoloration is not seen below 1,000 sterilization cycles. 
  • POM-C medical grade
    TECAFORM AH MT shows no significant loss of the mechanical properties until 800 sterilization cycles. However, discoloration may be seen at 200 sterilization cycles. At around 500 sterilization cycles, a color change (yellowing) may also be seen.
  • PP medical grade
    TECAPRO MT shows no significant loss of mechanical properties until 800 sterilization cycles. However, discoloration and color change (yellowing) is seen at 200 sterilization cycles (does not apply to TECAPRO MT black). 

Sterilization tests were performed using plastic test specimens without cleaning cycles. The sterilization temperature was 273.2°F with a sterilization time of 10 min. and a drying time of 20 min. The chamber pressure was 3 bar. Other effects influencing the cleaning process (with Ecolab, Borer etc.) were not investigated. Due to the chemical resistance of the individual materials and practical experience it must be assumed that the cleaning cycles have a significant influence on the sterilization resistance. The sterilization resistance, in particular of PP-HT and to a lesser degree POM-C, is significantly impaired by this. It must therefore be assumed that the sterilization resistance will be significantly lower than described. We typically define PP-HT with approx. 200 sterilization cycles and POM-C with approx. 300 - 400 cycles.

other sterilization methods

Hot air

With hot air sterilization, germs are killed off by dry heat under high thermal load (356°F) over a period of at least 30 minutes. This process is no longer permitted due to a large number of uncertain factors and has therefore now been replaced by other methods in most cases.

Medical grade materials which are very resistant to hot air are:

  • TECAPEEK MT
  • TECAPEEK MT CF30
  • TECAPEEK MT CLASSIXTM

Resistant MT materials are:

  • TECASON P MT

TECAFORM AH MT and TECAPRO MT are not resistant.

Plasma

Sterilization with hydrogen peroxide plasma is suitable for all plastics, however, it is costly and requires elaborate equipment. Highly reactive hydroxy and hydroxyl radicals kill the microorganisms at temperatures of just 113°F over periods of 45 to 80 minutes; the plasma is removed by ventilation. The risk of corrosion is almost non existent, and there is no toxic residue that would require prolonged degassing.

Medical grade materials which are resistant to plasma are:

  • TECAPEEK MT
  • TECAPEEK MT CF30
  • TECAPEEK MT CLASSIXTM
  • TECASON P MT
  • TECAFORM AH MT
  • TECAPRO MT

Formaldehyde and ethylene oxide

Sterilization using a microbiocidal gas such as formaldehyde or ethylene oxide is always carried out at temperatures between 118.4 and 140°F. Due to the low temperatures, this process is suitable for temperature sensitive materials. The efficiency of formaldehyde is comparable to that of ethylene oxide, but its lower toxicity permits shorter degassing times. Both are mainly used for disposable articles.

Medical grade materials which are resistant to gas are:

  • TECAPEEK MT
  • TECAPEEK MT CF30
  • TECAPEEK MT CLASSIXTM
  • TECASON P MT
  • TECAFORM AH MT
  • TECAPRO MT

Sterilization by gamma radiation

Sterilization by radiation is a gentle method that is suitable for almost all types of plastic and uses either gamma rays or a beam of highly accelerated electrons. These processes are cost and equipment intensive, so they are mainly used for sterilization of disposable products on an industrial scale.

Medical grade materials which are resistant to gamma radiation are:

  • TECAPEEK MT
  • TECAPEEK MT CF30
  • TECAPEEK MT CLASSIXTM

Resistant MT materials are:

  • TECASON P MT

TECAFORM AH MT and TECAPRO MT are not resistant.