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Baking soda label acts as a freshness timer

Special label eliminates replacement guesswork for a refrigerator air filter.

WS Packaging Group ( has solved a long-standing consumer conundrum of knowing when to replace the Arm & Hammer brand Baking Soda refrigerator air filter.

The “replacement indicator” was developed exclusively for the New FridgeFresh™ Refrigerator Air Filter. The consumer activates the label my removing a middle overlay via a pull tab. The white bar on the label turns pink as time passes. When it is completely pink, there’s no guessing about when it’s time to replace the air filter.

The product, which debuted a year ago and sells for around $3, is sealed inside a paperboard-backed blister. A base on the blister permits the pack to stand upright while a die-cut hole permits peg display merchandising.

Microencapsulation process

The pressure-sensitive label uses a chemical reaction between two microencapsulated proprietary materials to signal when it’s time to replace the air filter. Key objectives of the project were to make the label highly functional and easy to use. It also had to be applied to the front of the product, but not interfere with the functionality of the air filter device.

Church & Dwight of Princeton, NJ, the parent company of Arm & Hammer, had an aggressive timeframe for launching the air filter that WS Packaging met. That was despite the technological hurdles of engineering a multiple-ply construction that had never been done before...all in a period of two months.

Four-layer construction

The pressure-sensitive labels are produced in a single pass on a flexo press at the WS Packaging facility in Neenah, WI. The construction includes the label material, proprietary inks used for the indicator, a separation strip the consumer removes to activate the indicator, and a top ply.

The “New FridgeFresh Refrigerator Air Filter” was launched nationally May 2006 in retail and grocery stores. The product can be placed in the freezer or refrigerator and should last three months in the refrigerator and six months in the freezer. The flow-through design of the filter exposes twice the baking soda as the regular 1-lb box.
--Rick Lingle

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