Understanding the forces in TUFFs

TUFFs are designed to handle three primary types of force, depending on the application:

1. Engagement force 

   This refers to the effort required to ‘lock’ the engagement elements of the TUFF with the counterpart loop material. In simple terms, it’s the force required to close the fastener. As TUFFs are ‘touch-activated’, very little force (<1N) is typically required to suitably capture adequate numbers of fibres or filaments into the engagement elements and create an effective closure.

2. Disengagement force 

   The disengagement force is the opposite of engagement force—it’s the effort needed to ‘unlock’ or separate the fastener. Depending on the vendor and particular model of TUFF, disengagement forces are typically measured in the form of ‘peel’ strength.

3. Shear force 

   Shear force measures how well the engagement elements resist sliding against each other when a force is applied perpendicularly to the fastener.
   For example, think of a picture hanging on a wall or a diaper ear tab on a diaper landing zone/backsheet—the weight of the picture or the elastic pull of the ear tab applies a shear force to the fastener.

Why ‘fuzziness’ (fluffiness, high bulk) matters

If the counterpart material has a very fluffy or fuzzy tactile quality, it can be difficult for engagement elements in TUFFs to capture and retain enough fibres or filaments to create a good attachment (sufficient peel and shear strengths). In these cases, it is best to discuss your need with one of Binder’s Application Engineers for recommendations as to which TUFFs you can consider evaluating further.

For reliable and repeatable fastening solutions, Binder’s TUFF fasteners are an excellent choice.