The news recently focused on microplastics and their environmental impact. This triggered an awareness campaign about what these substances could be used for in cosmetics and about their effects on the environment. Following this, restrictive measures were enforced and others are scheduled for later on. Cosmetics formulas can contain several types of microplastics, but all of them do not have the same level of interest. Let’s focus on one of them – maybe the most important and interesting: nylon.
The most beautiful fabrics include those based on silk: they are particularly appealing due to their pleasant feel. But natural silk production makes them very expensive. That is why, as soon as the late 19th century, chemists tried to produce artificial silk in large quantities for low costs. In 1843, Hilaire de Chardonnet and Auguste Delubac invented viscose, artificial silk based on cellulose and collodion. It boosted the research of many chemists trying to create synthetic products with new properties. That is how nylon was developed a few decades later.
Nylon is a plastic material which belongs to the polyamide category and is widely used in the textile industry. Much praised for its strength and appearance similar to silk, nylon is now used in many types of clothes: nylon tights or stockings, underwear, windbreakers, sportswear, linings… and even toothbrushes, fishing nets, and cosmetics in general.
The invention of nylon marked the beginnings of the industrial development of synthetic fibres. This synthetic material belongs to the polyamide family and is obtained by hot condensation of a substance with two acid functions and another substance derived from ammonia: nylon 6-6 is obtained by hot polycondensation of a carboxylic diacid and a diamine. Wallace Hume Carothers, chemist at Harvard University, was hired as soon as 1928 by American company Du Pont de Nemours, the first to develop the material. Based on fundamental research on polymerization processes, he achieved two outstanding breakthroughs. In 1932, his division’s work led to a patent for neoprene, a synthetic rubber endowed with excellent light and heat resistance qualities which can also resist against most solvents. Then, in 1935, Carothers obtained nylon, a polyamide based on which he produced elastic, resistant fibres adapted to weaving. The industrial production of nylon started in 1938.
The nylon material is patented, but the term “nylon” was never registered as a trademark, so there is no need to use a capital letter to name it. There are many etymologies about the origin of this word, like those according to which it comes from NY (New York City) and LON (London). In 1938, a three-member committee at Du Pont de Nemours was appointed to decide how to name it. They chose nylon, so that American and British people could pronounce it the same way. Also, it is allegedly the acronym formed with the first name initials of the wives of the five Du Pont de Nemours chemists who discovered it together:
Nancy, Yvonne, Louella, Olivia, and Nina.
The term nylon gradually covered an increasing number of polyamide substances, like nylon 6-6, but also 6-4, 6-9, 6-10, polyamide 11, called Rilsan or French nylon, and polyamide 12. Perlon was part of this family, like Kevlar, a derivative (aramid). If, as soon as 1938, toothbrushes with nylon hair were the first industrial application for nylon, the one that really made it successful was invented in 1940: women’s tights. During WWII, nylon was also used to make parachutes. Then, it was incorporated to raincoats, underwear, swimming suits, socks, and sportswear, among others.
Nylon in cosmetics
Nylon and its derivatives are used for many applications. The adventure in cosmetics started as soon as the 1950s with applicators, like mascara or nail varnish brushes. These devices were very soon made with a particular fibre developed by Du Pont de Nemours, Tynex. The properties of this nylon derivative helped make accessories more easily. It is still used as a base to make mascara applicators, as well as nail varnish brushes. If one kilo of Tynex is needed to make “only” 1,000 toothbrushes… it is enough for 10,000 mascaras and 40,000 nail varnish brushes.
Beyond uses in packaging, another use gradually emerged: formulation. It all started in the early 70s, when ATOChem, a subsidiary of ELF Aquitaine, identified a market for polyamide powders, in particular in Japan. Contrary to powders usually obtained by crushing, these products were directly generated by polymerization based on a mineral kernel (silica). They were developed in Normandy, right where French nylon varieties were developed. These powders were characterized by structure differences, in particular porosity. They were named Orgasol®. In 1977, a production intended for experimental studies was shipped to Shiseido, in Japan. As the first results were encouraging, the official launch of Orgasol powders was announced in late 1982. They were named Orgasol® 2002 D Nat Cos for an average particle size distribution of 20 microns, and Orgasol® 2002 D Nat Extra Cos for 12 microns.
At first, they were used to fix additives, permeate certain substances, or enhance the skin application of powders, in particular face powders. As a result, the main cosmetics operators referenced these substances for this type of application, and the use of these nylon-based micro-sponges was soon oriented towards permeating substances that were difficult to manage: perfumes, liposoluble vitamins, various fats, and also actives in a number of makeup formulas. The transformation of these actives to permeated matrices helped incorporate them to many environments specific to the cosmetics industry.
The applications that most frequently integrated these specialties also included pressed powders. If application enhancement was one of the uses initially intended, this use was more common and technically outstanding. Indeed, the problem of powder compacting is often tricky – the ingredients’ hardness and structure can be incompatible with the process. Specific compacting techniques were developed starting from the 1980s, like compacting into different shapes or embossing. Contrary to what was usually done previously – buckets with a plane surface were needed – compacting technologies evolved towards different objects with rounded, trapezoid, or pyramidal shapes. Embossing techniques were also used to make specific preparations. The idea was to print a particular acronym on the product surface. But the nature of the materials used to make these products was hardly compatible with this compacting method. So, given their elastic properties, nylon powders helped apply lower pressures and obtain special shape compacts that both exhibited good strength and sufficient and satisfactory product delivery.
How come? During the compacting process, powders are subject to pressure, which creates gradients of different pressures depending on the shape. Nylon-based powders are more compatible with pressure differences due to product geometry, contrary to quarry materials, like talc or Mica. Other compact shapes were soon used and became major indications, as can be seen with products of a particular type, like Pastel Teint by Bourjois or Poudre Douce by Chanel.
They will constitute bestsellers for each of the brands. These are compact powders in the form of a compacted powder dome. These products, initially developed on the basis of wet forming technologies, presented numerous defects in addition to the difficulties linked to a complicated process. The use of a substantial dose of nylon powder in these preparations has made it possible to switch to a direct compaction mode guaranteeing both a superior cosmetic quality but also from the qualitative point of view a satisfactory appearance, improved forming, without defects or defective. The small nipple at the top of the dome, barely visible, will be serendipitous, but will also be a significant aid to compaction. If the Faceted Powder was quickly discontinued, the Soft Powder will remain in the Chanel catalog for many years, available in many versions.
Pretty soon, global compacting leaders adopted this product as a compacting attitude, like Intercos and many other compacting specialists.
And as the green and organic wave completed the arsenal of substances available to formulators, Orgasol® products also became “green” and organic. Since these substances were usually obtained from botanical fatty acids, the transition towards enhanced qualities was rather quick. That is how an “organic” variety with characteristics much similar to the initial products’ was developed, allowing for similar uses.
In addition, since permeation techniques could prove tricky, the manufacturer soon to be known as Arkema decided to implement the technique himself in order to offer pre-permeated powders in the form of matrices containing interesting substances. This decision helped laboratories with less equipment also have access to this product. The evolution of makeup products towards skincare claims made this growth possible.
What about tomorrow?
Organic, vegan and other criteria are already satisfied. The risk is related to regulatory issues. Today, nylons are considered as microplastics under the ECHA regulatory proposal. If this draft proposal was to be adopted in its current state, Nylons 12 and 11 would be banned in leave-on cosmetic formulas six years after the regulation was adopted. This would cause problems for their users in that the performance and multifunctionality of Orgasol® are still unequalled. There is no real satisfactory alternative. And although the progress made with the most recent compacting machines makes the operation less dependent on formulation than in the past, the ban on these ingredients would be harmful. No doubt it would make the art of formulating this type of product regress.
In a recent work, the Shiseido company develops a foundation formulation which reproduces the effects of stockings in a makeup product. According to the developers, this improves the distribution on the skin surface as well as the wear. Nylon has not finished making headlines, even if we use it anymore!
Many thanks to Arkema for their precious help in preparing this publication.
Jean Claude LE JOLIFF
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