Three questions about drying plastics that everyone should know how to answer. The quiz first appeared in the January 2011 article, "You Must Dry Hygroscopic Resins,"
by John Bozzelli.
Q 1. Molecular sieves are often used in desiccant canisters to extract the moisture from the air circulating through the dryer. At what temperature should these desiccant canisters operate to keep the air dry?
A. Molecular sieves operate best at 120 to 130 F.
Q 2. What is the proper temperature needed to drive the moisture off the desiccant for regeneration?
A. For molecular sieves, regeneration temperature is 410 to 450 F. For cone ceramic type, 350 F.
Q 3. What is the only correct method for measuring moisture in plastics—weight loss or moisture-specific analysis?
A. Moisture-specific is the only correct method!
Although pellet drying is a relatively simple process, it is occasionally a source of consternation.
Processors today face bewildering choices of at least five basic types of dryers, whose capabilities are subject to conflicting claims from equipment suppliers. For the buyer, the most basic questions are: How much drying is needed for the job and which dryer types are up to the task?
Take the guesswork out of drying with new technology.