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The use of change indicators is becoming more common in disposable hygiene products. You may find them in diaper briefs for infants and pull-up underwear for adults with moderate to heavy incontinence, especially in caregiver settings. In particular, hot melt wetness indicators (HMWI) are designed to change colour when exposed to an insult from inside the diaper. 


Benefits of Hot Melt Wetness Indicators


Hot melt wetness indicators offer a variety of benefits to consumers and to you as a manufacturer. Among them are:

  • Making it easier to spot when changes are needed
  • Helping to protect the wearer from skin irritation and other issues caused by prolonged exposure to wetness
  • Assisting caregivers in minimising wasted diapers due to unnecessary or premature changing
  • Differentiating your product from competitors by providing “added value” for the consumer 

What Attributes to Look for in a Hot Melt Wetness Indicator


It is important to note that not all HMWI are created equal. To work effectively, they must perform quickly, easily, and consistently. This requires testing for several attributes.

  • Fast and clear colour change after insult. It should be easily visible, even in dim light, such as when the baby, incontinent adult, or patient is sleeping.
  • Resistance to humidity. This prevents premature or partial indications from occurring during processing and storage, or even in use before insult. 
  • Reliable processability. They should process cleanly on the production lines and apply neatly to the substrate.
  • Thermal stability. The indicator must function even if the hot melt spends several days in production line melt tanks. This is not uncommon, as often very little is used per diaper.

As you evaluate the performance of your disposable hygiene products, keep in mind that your supplier should be able to provide you with performance testing results for their products. Additionally, they should be able to offer insights on how to choose the right products for your various application needs.