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Blend of equipment produces PP coffee capsules

Issue: July 2018

Kuhne Maschinenbau GmbH, US Extruders, Kiefel and Pro-Systems Integration are combining their technologies to offer a new high-speed, high-output system for manufacturing PP capsules used in single-cup coffee makers.

The Kuhne Smart Sheets extrusion line uses five extruders to produce seven-layer PP-based barrier sheet./ Kuhne USA/Canada

Kuhne and Kiefel offered information about the new system at NPE2018. Kiefel is a member of Brückner Group.

On June 21, the companies presented a Cup Day program at US Extruders’ headquarters to announce details about the collaboration, answer questions about the new technology and demonstrate the equipment in operation. Kuhne’s flat film and sheet division has partnered with US Extruders to promote Kuhne’s film and sheet lines in the North American market and provide service for any line sold.

A Kuhne Smart Sheets extrusion line uses five extruders to produce seven-layer PP-based barrier sheet. The sheet is fed in line to a Kiefel Thermorunner KTR 6.1 Speed thermoforming machine with a Bosch Sprang 91-cavity tool to produce up to 145,000 capsules per hour or about 1 billion annually based on a 24/7 schedule.

For the North American version of the Kuhne Smart Sheets line, US Extruders is supplying four of the five extruders, while the high-speed extruder will be Kuhne’s. ProSystems is providing the cabinets for the US Extruders machines, which will be integrated with Kuhne Controls.

The seven-layer sheet structure is A-B-D-E-D-B-C.

The system used for the Cup Day demonstration consists of the following extrusion equipment:

• One Kuhne KHS70EE-33D high-speed extruder equipped with a 70mm screw with a 33:1 L:D ratio with a throughput of 1,300 pounds per hour for the B layers of the sheet. The regrind generated by the skeleton from the thermoforming of the coffee cups is recycled in this layer, accounting for 45 percent to 50 percent of its content.

• Two US Extruders coextruders with 2.5-inch-diameter screws and a 30:1 L:D ratio for layers A and C, the skin layers. These extruders have a throughput of 250 pounds per hour. Using two extruders allows for different colors on the inside and outside of the cups.

• Two US Extruders coextruders with 2-inch-diameter screws and a 24:1 L:D ratio with a throughput of 100 pounds per hour for the D tie layers, made of a PP-based adhesive resin, and the ethylene

PP coffee capsules

vinyl alcohol (EVOH) barrier layer E. The EVOH layer extends the coffee’s shelf life.

The European version of the system, which debuted at a March 22 open house at Kuhne’s international headquarters in Sankt Augustin, Germany, featured all Kuhne-brand extruders.

“The Kuhne part of this project was the extrusion, where we use our sophisticated high-speed technology on the base layer and doing with our feedblock technology very precise distribution of the barrier inside the sheet with a very, very high-quality level,” Kuhne Maschinenbau’s managing director, Hubert Armbruster, said in a video produced by the company to promote the technology.

All the extruders are configured with melt pumps for metering the melt and pressure into the feedblock. The melt pumps provide individual layer and total thickness uniformity.

The extrusion line also is equipped with a Kuhne flat die; a Kuhne KU7 feedblock that has a proprietary lamella design producing seven layers, with the more expensive barrier and tie layers fully encapsulated within the other PP layers; and a Kuhne GA4-900 roll stack with 16-inch diameter rolls and a 35.4-inch width for an effective sheet width of between 27.6 inches and 31.5 inches.

The Kuhne-Kiefel partnership provides a more cost-effective alternative to the traditional PS-based coffee capsule, the companies said. The cost of PP resin is lower and PP is lighter, which saves weight. In addition, the PP coffee capsules are easily recyclable.

The in-line system also is energy-efficient, said Stephen Montalto, the director of sales for US Extruders. The sheet is still warm as it is fed into the thermoforming machine.

“You are not using as much energy to reheat the sheet when it is in line,” Montalto said. “It is coming right off the roll stack.”

Bruce Geiselman, senior staff reporter



Brückner Group USA Inc.,

Portsmouth, N.H., 603-766-6350,

Kuhne USA/Canada,
Charlotte, N.C., 980-417-2722, 

ProSystems Integration,
Westerly, R.I., 401-377-8500,

US Extruders,

Westerly, R.I., 401-584-4710,