Igloo Products Corp. envisions a quick payback on a Twinshot coinjection system that Spirex Corp. installed.
Igloo uses the system to mold ice chests — including liners of reground polyethylene — and projects a payback of less than two years.
“It is a good thing anytime you get a two-year payback on a large investment,” said Steve Little, Igloo injection molding process engineer.
“We were selling so much scrap to dealers,” Little said. “This project works for us” by allowing Igloo to use regrind instead of virgin resin in the mold core.
Katy, Texas-based Igloo began investigating Twinshot technology in early 2008. The company received delivery of the system in mid-October and was manufacturing product in mid-November.
Igloo encapsulates the foam PE insulation liner between layers of fractional-melt PE that form the interior and exterior of an ice chest. From separate hoppers, the skin material enters the mold first, and then the core material follows.
The two-stage Twinshot screw has independent melting sections for the materials, which then run through a traditional barrel. Multizone temperature controls are used. For Igloo, the result is an ice chest with a three-layer sandwich construction.
Previously, Igloo used polypropylene for the liner.
Consistency of the Twinshot system surprised Little.
“I anticipated we would have areas where the PE would show through the finished product,” he said. That didn't happen because the system “purred like a kitten,” he said.
Russell Cannon, Spirex senior process technician, installed the system as a retrofit on one of Igloo's three 1,500-ton Krauss Maffei injection molding presses from Oct. 21-23. Completing replacement of the screw and barrel “takes some work on larger tonnage machines,” Cannon noted.
An end user needs to evaluate what it wants the coinjection system to do and deal with core fluctuation. “You have to find out the percentage of core material” in order to gain the benefits, Cannon said.
Operators control the resin volume by varying the speed of the primary or auger feeder screw. Little acknowledged a learning curve with the technology.
“It takes an effort to get the system going and understand the process,” he said.
The Twinshot operates with a 23-1 length-over-diameter ratio and a 120-millimeter-diameter measurement inside the barrel and outside the screw. As a rule of thumb, a Twinshot system costs $1,000 per millimeter of screw diameter, said Mark Colella, general manager with Youngstown, Ohio-based Spirex.
Prior to installing the Twinshot equipment, Igloo sold scrap from its blow molding operations to a wholesaler, Little said.
“There are a lot of other applications for this” technology, including product decoration or handle encapsulation, Little said. “We can experiment.”
Igloo Products employs 1,200, occupies 1.4 million square feet of space and operates 55 injection molding machines ranging from 165-1,500 tons of clamping force. The company also has 51 blow molding machines.
Igloo designs, manufactures and markets personal and full-size ice chests and cooler models for beverage, soft-sided, patio and thermoelectric applications.
Private equity firm J.H. Whitney & Co. of New Canaan, Conn., acquired Igloo from Westar Capital LLC of Costa Mesa, Calif., in October.
Spirex created a commercialized version of coextrusion technology that originated from a concept from Community Products LLC, a playground and specialized equipment maker based in Rifton, N.Y. Spirex is the exclusive licensee, marketer and manufacturer of the system from patent-holder Twinshot Technologies, a Community Products business unit.
Spirex introduced Twinshot in 2001 and has sold 105 units, including 21 to Nampac Inc., a Raleigh, N.C.-based pail and rigid packaging molder.
