Aquaguard NK12, Sodium benzoate and potassium sorbate, 1 l

Aquaguard NK12 is a liquid preservative based on two salts of organic acids, sodium benzoate and potassium sorbate, dissolved in water. It is added to the formulation as a ready-made solution directly into the water phase and protects the product against microbial spoilage. It preserves without formaldehyde, formaldehyde donors and parabens, and thanks to its COSMOS Approved certification it can also be used in natural cosmetics.

The ready-made solution is its main practical advantage over powdered salts: there is no need to weigh two raw materials, dissolve them or deal with the risk of undissolved particles. It works at acidic pH, so it belongs in formulations whose pH is set in the acidic range.

Key properties

• Two active ingredients in one solution – 30% sodium benzoate and 15% potassium sorbate in water, ready to be added directly.
• Free from formaldehyde, formaldehyde donors and parabens – an alternative for formulations in which you want to avoid these groups of preservatives.
• COSMOS Approved and Vegan – can be used in certified natural cosmetics, with no raw materials of animal origin.
• Readily biodegradable according to the OECD 301 methodology.
• Wide range of uses – face, eye area, lips, body, hair and scalp, oral hygiene and children’s cosmetics.
• Miscible with water and glycols, which makes it easier to incorporate into serums, toners and emulsions.

Use in a formulation

The preservative is added in the cooling phase, at a temperature below 80 °C. In emulsions, that means only after the oil phase and water phase have been combined, while the mixture cools under constant stirring. In cold-processed products such as toners, gels and cleansing products, it is stirred directly into the water phase without heating.

The recommended usage rate varies by product type:

• Leave-on products (creams, serums, toners, body lotions) – 1.0–1.5%.
• Rinse-off products (shower gels, shampoos, bath products) – 0.8–1.3%.

The decisive condition is a finished product pH in the range of 2.0–5.5. Adjust the pH before adding the preservative and check it again after incorporating it. This preservative system is not intended for formulations with neutral or alkaline pH.

Suitable for products such as

• Toners and facial serums with acidic pH, into which the solution is stirred without heating.
• O/W creams and body lotions, added while the emulsion cools.
• Shower gels, bubble baths and shampoos, where a lower usage rate from the range for rinse-off products is sufficient.
• Deodorants and antiperspirants with a water phase.
• Lip balms and lip products and oral hygiene products.
• Children’s cosmetics with a water content, if the formulation meets the required pH range.

Good to know

The appearance of the solution ranges from colourless to a yellow to brownish liquid. In clear products such as toners or gels, it is worth checking the effect on colour on a small sample.

Like any preservative system, this one needs its efficacy confirmed in the finished product. A reliable answer comes from a challenge test of the finished product, not from following the usage rate alone.

The product is subject to classification under the CLP Regulation and is marked with the GHS07 pictogram (irritant, sensitisation, mild toxicity). The classification applies to the concentrated raw material. When working with it, follow the safety data sheet, which is available for the product.

The solution is also miscible with glycols. You can therefore add it to a glycerine or propanediol premix, for example together with water-soluble active ingredients, before combining it with the main water phase.

Frequently asked questions