Many preservatives commonly used in detergency are being discontinued due to regulatory changes. This, together with the tendency to formulate with substances that respect health and the environment, generates the need to find new alternatives to conserve detergents.
Sorbates: non-sensitizing preservatives existing in nature
Sorbates are molecules found in some natural products, such as mountain ash berries. Their synthetic analogues are used as preservatives in multiple applications, such as food, feed, pharmaceuticals and cosmetics, performing a preservative function that ensures microbiological stability.
Since they are biocidal agents, their industrial use is regulated by the Regulation (EU) 528/2012 (BPR), and they must be registered. Celanese is the only manufacturer to offer Nutrinova® Potassium Sorbate BFX Granules and Nutrinova® Sorbic Acid BFX DF as biocidal ingredients authorized for use as preservatives (PT6) in detergent formulations.
Sorbates present bactericidal and fungicidal action at use levels of 0.1 – 0.4%, if pH is appropriate. Celanese demonstrates a preservative efficacy of its sorbates in applications such as manual dishwashers, fabric softeners or multi-purpose acid pH cleaners.
- Effective against bacteria, fungi and yeasts at doses 0.1-0.4% in detergent formulations at pH≤7.
- Non-sensitizing, suitable for products “without label H317”.
- Suitable for isothiazolinone-free formulations at pH≤7.
- Identical to natural compound and compatible with most eco-labels.
- Neutral smell.
- Excellent safety profile, safe for humans and the environment.
Effectiveness and pH
Sorbic acid is an organic acid, and its preservative efficacy is superior in acid pH formulations. If the product is at pH>7, almost all of it is in the form of salt (sorbate), with a lower preservative activity.
The effectiveness of the preservative, therefore, depends on the pH. The lower the pH, the greater the proportion of sorbic acid available against the sorbate, and, therefore, it will have a better preservative effect.
However, the acid form is not very soluble in water, which makes it difficult to incorporate directly into the formula. It is usual to incorporate the product in the form of potassium sorbate, and by adjusting the pH in the formula, to achieve that a fraction is in the form of acid.
- Manual liquid dishwasher.
- Fabric softeners.
- All-purpose cleaners at pH≤7.
- Acid laundry detergents at pH≤7.