Ultramarine blue is the synthetic form of a naturally occurring mineral called Lapis Lazuli. From the time of the Pharaohs, Lapis was widely used in jewellery and as the blue pigment in high quality decoration. It was the discovery of its beneficial effects in laundering applications - and the resulting increase in demand - that led, in 1828, to the development of a process for manufacturing the pigment on an industrial scale. The natural product was neither abundant nor cheap nough to justify its use as a laundry aid.Ultramarine soon became widely accepted as the ‘blue whitener’.From its roots in the laundry industry, Ultramarine expanded into plastics, cosmetics, paint, artists’ colours and numerous other industries. But still a significant proportion of the thousands of tonnes of Ultramarine manufactured each year is used to improve the whiteness of laundered articles.
As natural fibres age, they tend to become yellower in undertone. This is undesirable since in most societies, it is a bluer undertone white that suggests higher quality and cleanliness. The advantage of Ultramarine when used in the laundering process stems from its ability to absorb the unwanted yellowness in white articles and replace it with the much more desirable blue undertone. Its effectiveness is due to the particular reflectance characteristics of the pigment. Ultramarine has a red undertone, which means it reflects at both the blue and the red extremes of the spectrum and absorbs only the unwanted yellow component. Most other blues are of a green undertone. In addition to absorbing the yellow component they also absorb the red and cannot therefore give such a balanced correction as Ultramarine.
The Ultramarine can be used to give a uniform pale blue colour to the detergent, or it can be concentrated on some of the granules which gives an attractive dark blue speckle effect in an otherwise white detergent. In either case the recommended addition level is around 0.15% based on the total detergent. The speckles suggest a special additive in the product which can be useful in marketing.
Ultramarine improves the undertone of white laundered articles giving improved whiteness, but cannot increase the reflectance to give improved brightness. This is only possible by using an optical brightener, which converts invisible ultraviolet light (UV) into visible light. Many blue pigments absorb UV light and would impair the efficiency of optical brighteners. Ultramarine does not absorb UV and combines well with optical brighteners, the one providing higher whiteness and the other higher brightness.
As the world becomes ever more sensitive to environmental issues, the implications of discharging chemicals from laundry operations into watercourses are being taken more seriously. Optical brighteners are very persistent and it is possible that in the future their use will be restricted.
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Benefits of Ultramarine for Laundry Applications:
Worldwide approval for use in skin contact applications
Optimum whitening effect
Does not permanently stain
Synergy with optical brighteners
Non-toxic
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