The Challenges of Delivering Long-lasting Fragrance with Liquid Fabric Softeners

Interview with Alain Phyfferoen,
Senior Technical Support & Development Manager, CP Kelco

Can you talk about some of the trends in liquid fabric softeners?

Scent is a major part of the fabric care experience, both for the elimination of odors and as an indicator of freshness. According to an Innova Market Insights category analysis, fabric freshener product launches grew by 7.8% from July 2016 to July 2021, and we see that “long lasting freshness” is often among top product claims. Many fabric softeners use oil or liquid fragrances to give an instant, short-term scent boost to the laundry; but together with the other components in the softener, a significant proportion could be lost in the drained rinse water. An alternative approach of using encapsulated perfumes can help as some encaps become entrapped in the fabric to provide a controlled release of fragrance past the wash-dry cycle. A consumer might use a towel or wear clothes weeks later and still pick up the scent.

If fragrance encaps can prolong fresh scents for weeks, why don’t more manufacturers use them?

There are two main reasons that are somewhat related. While encaps are a great vehicle for delivering long-lasting fragrance, there have been some challenges. First, there was a need for more sustainable encapsulation material. I’m sure we have all heard of the sustainability problems with microbeads. The plastic shells historically used can be harmful to the ecosystem. Microbeads can make their way past water treatment plants and into waterways. Thankfully, new biodegradable encapsulation chemistries have started to emerge. 

This leads to my second point: It can be difficult to keep biodegradable encaps stable and homogeneously distributed, especially in many types of fabric softeners with low concentrations of esterquats. Most liquid fabric softeners on the market today use a cationic quarternary ammonium compound, known as esterquats, to neutralize the charge of the anionic fabric fibers and reduce friction in the wash. When used at high concentration (e.g., 10%), esterquats can create a thickened system and encap phase separation issues are not usually observed. However, it could significantly increase the amount of fabric softener being lost in the drained rinse water. Most softeners today contain esterquat levels below 5%. At these levels, encap phase separation becomes almost unavoidable. This, in part, helps to explain why many current fabric softeners do not use encapsulated fragrance and cannot make claims on longer lasting fragrance.

Is there another technology to help manufacturers solve stability and suspension?

CP Kelco tested a new, cationic-compatible, nature-based stabilizer that can work in the presence of esterquats and is readily biodegradable. Our CELLULON^® RC-76 Cellulose Liquid is developed from fermentation-derived cellulose (FDC). Because it is produced through fermentation, it offers properties not possible with other sources of cellulose. For example, its fibers possess a very fine diameter and form a 3D net-like structure that provide a very high surface area-to-weight ratio. This can suspend most fragrance encaps. We conducted an independent panel test of our new FDC product in a fabric softener formulation containing 3% esterquats and a combination of 0.8% fragrance oil and 0.4% biodegradable, encapsulated fragrance with great results. The test showed an initial fragrance boost in the freshly laundered terry cloth fabric, plus the fragrance intensity persisted on the dry fabric over two weeks after washing.

How would you compare using cationic-compatible FDC to suspend fragrance encaps instead of using a higher concentration of esterquats?

CELLULON^® RC-76 Cellulose Liquid is easy to use and can be added at any point in the manufacturing process. The product typically requires high speed mixing to fully disperse, so it is often convenient to add it as one of the first ingredients to the freshwater. However, this is not required and, once added, it will quickly begin providing suspension capabilities to the formulation. It is also highly efficient and can provide stability at low concentrations, possibly even in low- or no-water formulations. Furthermore, the enhanced stability in a product can often mean that the formulation can be simplified and manufactured more consistently. Plus, using a readily biodegradable, nature-based solution can positively impact sustainability efforts.