When a product is sold only to professional licensed pesticide applicators, its packaging doesn't have the same safety requirements that would be needed for a product marketed to consumers. Still, when Bayer's Agriculture Div. found that it could improve the integrity of its container seals<>and gain tamper-evidence, too<>it jumped at the chance.
The result is a new 110-mm, TE polypropylene closure on a slightly modified 5"-diameter jar made of high-density polyethylene, introduced early this year. And it's believed to be the first wide-mouth TE closure ever used on a pesticide product. Made in Canada by Pano Cap, the closure is available through Pano's U.S. agent Pano Cap Canada Ltd. (Phoenix, MD). Just as important, according to Pano Cap Canada Ltd., the new cap is made from Pro-fax(TM) PP resin, supplied by Montell North America (Wilmington, DE).
The product is Tempo® Insecticide, a powdered concentrate that's available only to professional pesticide applicators. Previously packaged in a 5"-diameter jar of HDPE holding 420 g, the product of the Kansas City, MO-based manufacturer used a continuous-thread 100-mm PP closure with a pressure-sensitive polystyrene foam liner that served as an inner seal.
Seal integrity was Bayer's primary concern. "Although this product doesn't require either a tamper-evident or child-resistant closure, we wanted to upgrade the closure to improve our seals," says Jim McGreevy, Bayer's manager of packaging technology. Upgrading the closure was one objective; finding a wide-mouth closure with tamper-evidence was a far bigger challenge.
"Our approach to packaging, almost across the board here, has been to add tamper-evidency to our packages, [and] externally visible tamper-evidency," says McGreevy. "Our customers told us they didn't like the fact that they had to remove the closure to check whether the package had been tampered with.
"We went away from induction seals on 63-mm screw caps on all of our two-and-a-half-gallon jugs holding liquids. Instead we replaced that with caps that use visible, breakaway TE bands." There has been a concerted move throughout Bayer's Agriculture Division to add obvious TE to its closures.
Along with meeting customers needs, Bayer also sought to guarantee good seals. "Using the induction-sealed liners on our liquid products in jugs, there was no on-line method to test 100 percent of the containers for good seals," McGreevy points out. "We did random testing of seals, but we really wanted to be able to test all of our containers."
To eliminate the inner seal, Bayer sought a TE cap that would not be difficult to open. These challenges were tough to meet. Another complication: Most TE caps employ a breakaway band that easily separates from the cap when the cap is twisted off the container. Finding this in a wide-mouth finish was virtually impossible. "We finally discovered that Pano Cap Canada had a line of TE closures with tear-away bands," says McGreevy. "We brought this to the attention of our packaging distributor, Tricor Packaging of Kansas City."
How closure works
Unlike conventional TE closures, the patented Pano Cap is a one-piece cap that essentially becomes a three-piece closure in use. The closure is patented in the U.S. and in Canada. Properly applied to a container, the cap has a pull tab that allows removal of a ring between the cap and the TE band. The TE band stays on below a bead molded into the container; the cap is easily twisted off for removal. The three separate sections of the closure are connected by vertical ribs spaced 1/4" apart around the circumference. Opening instructions are molded into the top of the cap for convenience.
Pano offers the closures in sizes from 58 to 110 mm in diameter. Even though the new closure replaces Bayer's previous cap and inner seal, it's still about a penny/unit more costly than what Bayer used previously, McGreevy points out. "We felt it was more than justified by the improved intregity of the seal and the added safety features."
The patents indicate that this cap is not easy to manufacture. "We have worked with resins from Montell and its predecessor companies for more than 20 years," says Uwe Sendel, Pano's president. "When we developed this particular line, we knew that Montell could deliver the performance we needed. All of our development centered on Montell's Pro-fax SV-956 grade."
In a closure design like this, the "bridges" or connectors between the band and the closure are fragile, points out Randy House of Pano Cap Canada. "The resin is critical to stand up to the rigors of capping. The fine line is discovering how to make the band so it doesn't break away upon application to the jar, yet the band is still easy to remove to open the jar." The resin, says House, offers the stiffness of a homopolymer along with the enhanced impact properties that exceed those of typical PP closure grades.
Although Bayer found the right closure, it was too large for its existing container. Pano makes a variety of sizes, but it didn't offer the 100-mm size that would replace Bayer's existing closure. So, says McGreevy, Bayer faced the dilemma of mating the jar with the closure.
"We discovered that Pano makes both an 89- and 110-millimeter closure. But our jar was made with a 100-millimeter finish," he says. Bayer selected the 110-mm size to make sure that users could easily scoop out the powdered contents that are later mixed with water before application. So it began talks with jar blow molder, Container Technology (Independence, MO), to find a solution to the problem.
McGreevy admits that he had some doubts that the jar could easily be reconfigured to accept the 110-mm closure. "We were afraid it would make the cap wider than the body of the jar. But when we saw the drawing, it looked fine. We didn't want a container where the neck appeared to be wider than the body of the jar." The jar molder assured Bayer that changes in the neck rings on the HDPE jar would not have a noticeable effect on the jar's appearance.
Finally, the last hurdle was understanding what changes would be required on Bayer's packaging line in Kansas City. According to production supervisor Terry Lewis, only minor capper adjustments were required. "We made adjustments to the torque mechanism and to the tightening bands," he says, increasing the application torque to drive the TE band down over the bead on the jar.
Extended-text label booklet
Shortly before the closure change was made, Bayer had converted to a new Extended-Text(TM) pressure-sensitive label booklet supplied by Inprint Systems (St. Charles, MO). Those labels are pre-applied to the jars by an unidentified company before the jars enter Bayer's packaging line.
"Changing the finish on the jar didn't cause any major changes," McGreevy says. "It didn't change the capacity of the jar, the diameter of the jar nor the configuration of the case. In fact, we're doing the same product in the same net weight into arguably the same container<>except for the closure.
"The jar configuration is almost totally straight. It necks in only very slightly compared to the former jar. Still, the finish is within the profile of the sidewalls of the jar. There is no height or width increase, and no changes in the case."
Since the jar was virtually unchanged, the only modifications to Bayer's filling line were in the Kaps-All capper (Riverhead, NY) to accommodate the new closure size and torque requirements.
After the product is packed into the pre-labeled jars, the cap is torqued on securely. Just before the jars of Tempo are packed six to a corrugated shipper, a p-s label is applied to the top of the cap. It calls the pesticide applicator's attention to the multi-panel label and to the small plastic scoops that are packed with the jars in the case.
The scoop size has been changed to hold 5g of Tempo. It's molded by Tricor for Bayer. Like the jars and the closures, Tricor inventories the scoops for Bayer, so each just-in-time shipment includes all package components.
Unfortunately, the cap change is so recent that Bayer hasn't really had any reaction to the change. "We've only been shipping the new jars since February," reports McGreevy.
"The new caps are working well in our packaging operation," he says. "So far as I know, we haven't had any reports of any objections from customers, so we're satisfied that this has been a good investment for us."