Nanocomposite coating to boost moisture barrier performance, cut costs

13 Jan 2011

Lightweighting, cost reduction as well as improved oxygen and moisture barrier performance, are claims made by InMat for its new water-based nanocomposite coating for flexible packaging.

The US-based company said its Nanolok WR 20135a provides high oxygen barrier “over the widest relative humidity range (RH) range currently available in water-based nanocomposites”.

A one micron coating will provide an oxygen barrier that performs more than fours times as effectively as PVDC coated PET at relative humidity from 0-80 per cent. Its performance is almost twice as good at 85 per cent RH, said the firm.

“This coating also provides similar moisture barrier to that of PVDC coated PET when tested at 85RH and 40C. It is ~ 10x better oxygen barrier than EVOH (EVAL E) and 40 times better moisture barrier,” said an InMat statement.

CEO and president Dr Harris A. Goldberg said that these barrier improvements over the RH range were potentially significant in maximising the performance of flexible packaging to preserve product quality and maintain shelf life.

“It can be critical depending upon the type of food, the package design, and the storage conditions,” he said. “For example, meat and cheese packages have a high RH inside the package. Snack foods have a low RH inside, but are often stored in warehouses and trucks under high RH conditions. If the barrier coating is not the inside layer but closer to the outside of the package, it needs to provide barrier at whatever RH the package sees in storage and transportation.”

The company, headquartered in New Jersey, said its technology allows it to combine water-dispersed polymers with nano-dispersed clays into stable water based barrier coatings. Its products are environmentally-friendly as they contain no solvents or hazardous materials and are appropriate for food packaging applications, it added

Cost effective

Dr Goldberg also said the new coating is far thinner than comparable EVOH products – and therefore more cost effective.

“EVOH is often used at a thickness of 10 microns or more,” he said. “In those cases, we can replace the EVOH with a submicron coating, significantly reducing coat weight and providing a savings in the barrier material costs.”

The WR 20135 has double the amount of solid content than the company’s previous coatings, which reduces drying time and speeds up the coating process.

“The cost of applying a coating is inversely proportional to the speed at which you can apply the coating, and for most customers, the speed is limited by their drying capacity,” said Dr Goldberg. “Providing a coating with twice the solid content means that you can apply the same coat weight with half the water. This should translate into higher coating speeds and thus lower coating process costs.”

The coating meets compostability standards on bio-based films and in compliant with all European and US food contact standards, said InMat.

Source: InMat