Cleaning up colour: the search for non-staining, skin and fabric rinsable acid dyes
Colour is a key ingredient in many household cleaning and fabric care products. Marketers use it to create distinctive brands, to emphasize product qualities and to enhance the customer experience. But colour has a secret: many standard acid dyes do not rinse away completely in water, leaving residue that can, with repeated exposure, slowly discolour the fabrics and hard surfaces the products are meant to clean. Has a solution been discovered? Mike Pembery, Technical Manager, Sensient Industrial Colors, tells us about an Hi&i industry innovation.
MIKE PEMBERY LOOKS AT THE COLOUR CHALLENGES FACING MANUFACTURERS OF HOUSEHOLD CLEANING AND FABRIC CARE PRODUCTS
A particular shade of blue might denote the hygienic properties of a household cleaner. Yellow fabric softener can stimulate consumers’ senses so they perceive the product’s floral perfume to be more intense and evocative, while some brands of detergent have colours as recognizable to the consumer as the red of a famous Italian sports car. These are all attributes that marketers value, but they come at a price.
Manufacturers tell us they face a trade-off between ‘rinsablity’ and cost when choosing dyes. Premium brands tend to use expensive polymer-based acid dyes because the molecular size makes the colours almost completely
non-staining to skin; but if fabrics are discoloured they can be difficult to bleach out. Mass-market products tend to use standard acid dyes because they are cheaper and any gradual discolouration of whites is seen as an unavoidable side-effect that bleaching can sometimes solve (Figure 1 where bleaches can be used to reverse the effect shown).
SKIN AND FABRIC RINSAB ... ...