Paper is dipped in resin to improve moisture resistance but to much resin leads to a loss in porosity. Dry heat would work except no seals will hold at the heat. Used as a sealant since with hear, it will bond to a range of materials. Type of Packaging Type of Packaging Properties Flat Pouches Commonly made from Tyvek on one side with a clear plastic on the other. If steam sterilized then the paper provides the necessary porosity while the plastic gives the visibility desired.
Radiation sterilization allows for all plastic pouches.
Flat pouches are not suitable for bulky items. Peelabily and opening should be considered when designing flat pouches Vent Bags LDPE is commonly used for vent bags. Air gets trapped and expands during heat sterilization processes causing the bag to pop. Preformed Tray or Lid Provides more solid protection, allows for several items to be packaged together. Should be designed to nest within one another.