New technology takes the guesswork out of PET processing, say company

A new application allows plastic processors to use their mobile phone or tablet PC to calculate the intrinsic viscosity (IV) of PET resin in seconds, said the US company behind the development.

Plastic Technologies Inc (PTI) said its newly launched iPhone and iPad app will help a huge range of industry players across the manufacturing and processing sectors analyse moisture level impact on the intrinsic viscosity of PET.

The technology, claimed to be the first of its kind for the plastics packaging industry, has the potential to save companies “significant money” by removing the guesswork out of determining the correct final IV, as well as ensuring that material is fit for purpose, said the company.

Intrinsic viscosity

PTI said that IV has a significant impact on how PET resin will process. After the resin arrives at a processor’s facility, it is typically dried to remove as much moisture as possible before being used to create preforms and bottles.

“When you buy PET resin, the manufacturer has already indicated what its ideal processing IV should be,” said Scott Steele, vice president global analytical labs, training and enterprise projects, PTI. "However, due the basic nature of PET, the resin will have absorbed moisture which is why it needs to be dried before processing.”

He added that, typically, processors use their expert knowledge and experience to estimate what the actual viscosity is at the time of processing.

“However, without knowing the actual IV, you run the risk of creating packaging that doesn’t meet performance specifications,” said Steele.

The format, called a nomograph, uses a graphic representation of numerical values to produce a final calculation. The firm’s PET Hydrolytic Degradation Nomograph enables the user to indicate the starting IV by sliding a plot point on a vertical scale to the appropriate value. The same is done for moisture percentage. The two plot points are connected by a moveable line - with the intersection of that line, on a third vertical plane, is the material’s final IV, said the company

“We wanted to create a tool that was free, portable and easy-to-use," said Steele. “This nomograph calculates the final IV in a couple of seconds. The visual reference points are easy to plot and read.”

The company said the tool was ideal for plastic processors, resin producers, lab techs, plant production, equipment manufacturers and others involved in the PET process. It can be located in the iTunes App Store by searching for ‘PET nomograph’.