Alpla develops recyclable PP condiments closure for unwanted dripping control

18 May 2021 --- Alpla has developed a valve-less polypropylene (PP) screw cap with a flip lid for viscous liquids, such as ketchup, mayonnaise and honey. 

The fully recyclable cap allows for controlled dosing and prevents unwanted dripping for when dispensing contents too quickly or in too large quantities is undesirable.

The cap is also compatible with standard bottles and can be produced cost-effectively.

The launch aligns with Alpla’s 2025 goal of making all its packaging solutions fully recyclable. “We firmly believe that recycling design is a key success factor on our way to establishing an effective circular economy,” notes Steffen Kroon, Alpla’s sales manager of caps and closures.

Mono-material gains
Alpla highlights many commercially available PP caps contain a valve for more precise dosing made from an additional, easily moldable material – typically silicone or a thermoplastic elastomer (TPE). 

These standard caps open when light pressure is applied, and the contents can flow out of the packaging. The valve then closes again when the pressure is released. 

However, using a second plastic material compromises the cap’s recyclability. Silicone contaminates the PET or HDPE recycling streams, says Alpla, explaining why silicone caps are “increasingly forfeiting market acceptance.”

A simple dosing mechanism
Alpla’s new dosing mechanism employs the laws of physics for controlled squeezing. Squeezing the bottle creates a pressure difference inside the bottle. The bottle’s contents are diverted into a screw within the cap, which it has to pass before making it to the opening. 

At the same time, high negative pressure is created. When the pressure on the bottle is reduced, there is pressure compensation, and the content is drawn back in by the suction effect without dripping. Alpla notes the principle is similar to that of a drinking straw.

The cap retains a similar design as standard caps and meets all the market requirements. It allows for customer-specific adaptations and can be produced cost-efficiently.

Environmental strides
The Austrian packaging expert has made several recyclability enhancements to standard drinking bottles. These include a 1 L ultra-light refillable PET bottle in partnership with bottling and packaging systems company KHS. 

In 2019, the company partnered with paper packaging specialist BillerudKorsnäs on a groundbreaking project to develop a fully bio-based and recyclable paper bottle. Notably, Alpla laid claim to the world’s first carbon-neutral recycled PET last October. 

By Anni Schleicher

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