What you need to know about polyquaterniums stains

Polyquaternium stains are a persistent issue for commercial laundries. The culprit is a conditoning ingredient called polyquaternium-7. This polymer sticks to fabrics and causes non-removable dark stains. As a result, laundries face the cost of frequent textile replacement costs.

This blog post’s aim is to help understand and address this issue, and find effective ways to mitigate the problem.

What is polyquaternium? 

Polyquaternium is a group name for cationic conditioning polymers used in hair and skincare products. One of these polymers is polyquaternium-7. The polymer is used to moisturise, smoothen and seal damaged areas of the hair, to eliminate static electricity and to provide a silky feel to the hair.

Hairw with and without polyquat

Microscopic image of hair without polyquaternium-7 (picture 1 ) and with polyquaternium-7 (picture 2)

Polyquaternium-7 on textiles

In theory, shampoo or shower gel does not come into direct contact with textiles. But tests have shown that the protective film which is left on your hair or skin after washing with a polyquaternium-7 containing product, is partially rubbed off by the towel during drying. Consequently, these textiles will contain residues of the polyquaternium-7 compound. These residues do not stain the textile as such, because polyquaternium-7 is transparent and colourless. This makes it di­fficult for laundries to identify polyquaternium-7 stained textiles prior to washing.

Polyquaternium stains on washed linen

Polyquaternium-7 is a molecule of very high molecular weight consisting of up to millions of repeated linked units, each positively charged.

formula polyquat-7

Because of the size of the molecule and the high number of positive charges, it will link strongly with the negatively charged textile surfaces. Due to the permanently positive charge of the quaternary ammonium groups, polyquaternium-7 will act as a real “dirt-magnet” for the mainly negatively charged dirt, dust or dye particles in the washing liquor, resulting in dark stains on the washed textiles.

Washing test 

Christeyns’ R&D team collected shampoos and shower gels that are used by hotel chains and stained the textile with 30 types. Of these 30 products tested, 29 products contained polyquaternium-7, one non-polyquaternium-containing product was included as a reference. The experiment was repeated using different washing programs.

Towel with stains


For every washing program used, 29 dark stains appeared where the polyquaternium-7 containing products were applied, and no staining is observed where the reference product was applied.



How to avoid these stains?

Due to the very strong bond between the polyquaternium-film and the dirt, it is nearly impossible to remove the stains. That is why the best approach is to address the origin of the problem and avoid the use of polyquaternium-containing products.

A market study performed by Christeyns in the Netherlands showed that 30% of the hair and skin care products available in hotels contains polyquaternium-7. Very often, hospitality customers are not aware of the potential issue polyquaternium containing hair and skin products can cause. By advising them to switch the formulation of their shampoo and shower gel to non-polyquaternium containing products, these stains will be solved immediately.

Another solution to these persistent stains is a preventative approach. Christeyns’ R&D experts came up with a solution to prevent this type of staining: Smart ShieldSmart Shield, which is a special liquid to be dosed as additive in the pre-wash, neutralises the positive charge of the polyquaternium-molecule, thus avoiding the attraction of the negatively charged dirt and the formation of the stains.

Do you know these dark spots all too well? Don’t hesitate and contact your Christeyns expert to know more about Smart Shield.

This blog is also available as flyer.

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