SIG Combibloc launches screwtop closure for key carton

SIG Combibloc has launched a screwtop version of its combibloc EcoPlus carton for long-life milk and dairy products, which was first launched in August 2010 without a closure.

The company said that its new combiCap closure for the carton weighed 1.9g, 60% less than the first ever SIG Combibloc screwcap, and a SIG Combibloc spokeswoman said that it was an "extremely lightweight solution".

SIG Combibloc said it applied the screw cap on an over-coated hole that was punched into the raw paperboard before it was laminated.

“Thus the closure, which is applied to the carton pack after the product has been filled, can be easily opened by the consumer with a single twist, as the cardboard layer has already been removed and only the thin polymer layers need to be opened,” the company said.

Single-twist, tamper evident closure

The single-twist closure itself comprises a flange with integrated cutting ring and screw cap, which incorporates a tamper evidence feature (an audible click) when the product seal is broken.

Aside from the light weight of the combibloc Ecoplus, SIG also alluded to Europe-wide consumer tests that it said showed that cap was easy to open and offered a good pouring action

The spokeswoman added: "Handling tests in Spain, Poland and Germany have shown that combiCap is well-received by consumers, thanks to its convenient opening behaviour and smooth pouring action.

"Consumers are finding the closure mechanism very easy and comfortable to grip."

Carbon-saving carton

The carton itself (below and right) generated 28% less CO2 than a one-liter carton pack of the same format across its lifecycle, SIG said, where it differed from other cartons due to an 80% composite structure, a special type of wood-based paperboard.

A special new ‘razor-thin’ polyamide layer provided additional barrier qualities and protected products from flavor loss and external odors, the company added.

Finally, SIG said that fine polyethylene layers both inside the carton (where it formed a liquid barrier for the product), and outside (to keep moisture out) meant that the carton’s overall composition led to the CO2 savings.

As to where and how well the carton was performing, the spokeswoman said it was "making its debut in Germany".

"However, in many parts of the world the goal of reducing CO2 emissions is also growing in importance for business and, more and more, for consumers as well," she added.

"We are in discussion with several customers in Europe and see potential for combibloc EcoPlus with screw cap world-wide, too," she said.

The spokeswoman explained that its composite material was designed to suit the barrier requirements of UHT milk.

"But we are currently working on a CO2 -reduced composite that is adapted to work for the barrier requirements of non-carbonated juice products, as well," she said.

Source: SIG Combibloc