Polypropylene (PP) is a softer plastic and has a slightly milky color. PP has the advantage of being easily recycled at most recycling locations.
PES is a higher end plastic. It is clear with a slight honey color. PES can withstand super high heat. It is rigid plastic. PES can be recycled by sending bottles to a recycling plant that works with PES or back to the manufacturer.
Alternatives to Polycarbonate:
There are currently two types of substitutes for polycarbonate plastics, namely Polypropylene or Polypropene (PP) and Polyethersulfone (PES). PP has a melting point of 121 degrees Celcius.
PP milk bottles will loose their transparency over time, lessening their active useful life. When put into boiling water or sterilize cycles, PP bottles have a limited shelf-life.
PES plastic will retain their tensile strength and form with continuous use at temperatures as high as 180 degree Celsius (356 degrees Fahrenheit). PES is ideal for the construction of baby bottles because it can be safely and easily sterilized.
However, it’s worth mentioning that PES is one of those plastics that ended up in the #7 recycling category because it didn’t fit well into the other categories. This recycling category is also where Polycarbonate falls into. Therefore, do be mindful when you see #7 recycling category.
