Why Avoid Using Only Caustic Soda for Degreasing Felts

Why Avoid Using Only Caustic Soda for Degreasing Felts

1. Risk of Damaging the FeltCaustic soda is highly alkaline and, if used alone and at high concentrations, can:

• degrade the felt fibers (especially if synthetic or blended),

• harden or stiffen the material,

• shorten the overall service life of the felt,

• cause felting and reduce absorbency.

2. Partial Removal of GreaseCaustic soda is not an effective solvent for complex fats (such as animal lipids present in hides).Without the addition of a surfactant or suitable detergent, many fatty residues remain trapped in the felt, resulting in inefficient cleaning.

3. Difficult Chemical Residues to RemoveIf not thoroughly rinsed, caustic soda can leave alkaline residues that:

• migrate onto the hides during pressing,

• cause alkaline stains or surface damage,

• alter local pH and interfere with subsequent processing steps (e.g., finishing or dyeing).

4. Corrosion of EquipmentCaustic soda is highly corrosive to:

• metal components (especially non-stainless-steel parts),

• • seals and rubber or plastic elements.This can lead to equipment downtime and higher maintenance costs.