| Search | Feedback | Contents | Deutsch |
 |
| Issue 46 |  |
|||
| Printable version | ||||
| Category | Title | Authors | ||
| Newsletter | Cosmetotextiles - Skin care you can wear |
The types of textiles and their functions are continuously evolving, and today modern finishes can add a new dimension to a textile's function. Integrating cosmetics into textiles offers a unique platform for delivering such products while a garment is being worn. The increased convenience coupled with functionality converts cosmetotextiles into true “active” players that can help increase our sense of wellbeing.
The name “cosmetotextiles” has been coined to designate textiles with cosmetic properties, but these types of textiles can also be a vehicle for other active substances or functions, such as agents with medicinal properties, mosquito repellents, odor reducers, antimicrobials or UV-protection agents.
Research aimed at incorporating cosmetic compositions into textiles started to appear in the late 1980s with Japan leading the way. Europe followed this lead in 1995 when Hermes launched a scarf perfumed with encapsulated Calèche. This may well have been the first commercial textile in Europe coated with microcapsules. While the initial technology came predominantly from small innovative French companies such as Euracli, the turn of the century saw a significant involvement of large multinational companies, such as Cognis in 2001 and Invista in 2003, who launched their branded solutions for cosmetotextiles which they called Skintex® and Lycra Body Care. The year 2003 saw the creation of Lytess, the French textile brand exclusively dedicated to the development and commercialization of cosmetotextiles and now one of the European market leaders as a textile brand in this area.
Developing and producing effective cosmetotextiles that actually provide valuable benefits for consumers for a certain number of days of wear is challenging. On the one hand usually large amounts of cosmetic ingredients must be transferred to the skin while the cosmetotextile is being worn but, on the other hand, as little as possible should be lost when the textile is washed. Many cosmetic ingredients are heat-sensitive or prone to oxidation whereas others, such as perfumes, are volatile.
Microencapsulation as key technology
Microencapsulation is therefore a key technology for cosmetotextiles (Figure 1). Sensitive cosmetic ingredients are protected from degradation processes such as oxidation, polymerization etc. and can withstand drying and heat-setting processes. Volatile ingredients are prevented from evaporating, which increases their shelf-life. Water-soluble ingredients are difficult to encapsulate and are largely removed from the textile when washed. Therefore, lypophilic constituents are more amenable to cosmetotextile applications. Microcapsules can be modified in terms of their size, mechanical robustness and permeability to customize their release profiles for optimum performance in use.
Figure 1: Microcapsules on textiles
Enlarged version
Although the European Cosmetics Regulation was published in December 2009, it will come with only a few exceptions into force not before 2013. Presently cosmetic products are still defined in the European Cosmetics Directive, 76/768/EEC (7th amendment) as ‘any substance or preparation intended to be placed in contact with the various external parts of the human body or … with a view exclusively or mainly to cleaning them, perfuming them, changing their appearance … or keeping them in good condition’.
Figure 2:The sock with the moisturizing finish increased skin surface hydration
In the case of cosmetotextiles, the question may be asked whether or not they can be classified as cosmetics. The so-called borderline manual gives guidance on whether the Cosmetics Directive applies to certain products. According to this manual, “the textile is neither a substance nor a preparation .... However, the textile may be the “vehicle” to deliver a substance or preparation to the human skin. This substance or preparation, if it is intended to be placed in contact with the various external parts of the human body, … falls within the scope of application of the Cosmetics Directive.” It also states that other legislation, regulations or directives may apply in parallel, i.e. any legislation relevant to conventional textiles must also be taken into account. In 2009, CEN, the European committee for standardization, approved a technical report with the title “Cosmetotextiles”. For the first time, “cosmetotextiles” have an official definition, and guidelines on how to play the game of “skin care you can wear” are available.
Cosmetic efficacy is an integral attribute of true cosmetotextiles. The three key elements to be taken into consideration are: safety, quantity, and synergy.
• Safety: Cosmetotextiles contain cosmetic constituents, the use of which needs to be as safe as if applied via conventional means, e.g. body lotions. Qualified professionals are needed to ensure that the toxicological profile of the cosmetic ingredients and the textile auxiliaries used in the cosmetotextile’s finish are satisfactory.
• Quantity: The cosmetic functionality defines the amounts of a cosmetic product that are required to achieve efficacious performance. Skin care effects, such as moisturizing, require larger amounts of the cosmetic product to be used (e.g. body lotions) in order to achieve perceptible effects, whereas fragrances require only much smaller amounts to achieve their effects. Only a certain percentage of cosmetic ingredients per weight of the material can be incorporated in the textile and the amounts also depend on the fabric used (e.g. jeans are heavier than pantyhose). The use of systems to "reload" the cosmetotextile, e.g. sprays containing the cosmetic formulations required, can prolong the efficacy of the cosmetotextile.
• Synergy: In order to maximize efficacy, the fabric composition and construction, garment design and cosmetic finish must be attuned to achieve the best effects. To ensure satisfactory cosmetic performance when large amounts need to be transferred, it may well be best to use fabrics with a large contact surface to the zones of the skin to be treated. Elastic fabrics with some degree of compression and a certain massaging effect will often be helpful.
Sufficient amounts of the cosmetic product must be applied to the cosmetotextiles – and transferred to the skin in large enough quantity to ensure that cosmetic benefits are possible.
In order to ascertain whether transfer from textiles to the skin was taking place, twenty human volunteers were asked to wear a model cotton sleeve treated with microcapsules containing squalane and vitamin E acetate. After five and eight hours the transferred substances were extracted from the skin surface of ten volunteers per time point, using ethanol as a solvent. The results demonstrated that the cosmetic ingredients were in fact being transferred.
Cosmetic performance claims are demonstrated via a variety of different approaches and guidance documents have been published, for example by COLIPA. In general, claim types can be differentiated into two major classes – objective and subjective claims. Over the past two decades a number of biophysical methods have evolved to objectively measure skin attributes, and which are now routinely used for claim substantiation, for example corneometry to assess skin surface hydration. Subjective claims are often assessed via questionnaires.
To ascertain whether wearing a cosmetotextile can convey cosmetic benefits to the skin, in this case improved skin hydration (moisturizing), a study with 20 female volunteers with dry to very dry skin was conducted at an independent test institute. The volunteers were asked to wear an untreated stocking on one leg and a stocking treated with a moisturizing finish (Skintex® Monoi) on the other, for eight hours a day over 12 days. The subjects were instructed to hand-wash the stockings daily. With the exception of days five and ten, a statistically significant increase in skin hydration was observed on the treated side. The results are depicted in Figure 2. The greatest increase was observed after one day of wear and gradually decreased over the study period, which would coincide with a gradual depletion of the cosmetic from the stocking over the observation period.
Consumer preferences can also be evaluated via questionnaires. Jeans treated with a finish aimed at improving the outer appearance of cellulite (Skintex® Slimming) were tested in a home use test. Each of the 160 participants was given two treated jeans made from 97 % cotton and 3 % elastane and wore the jeans for 6 weeks - at least five days per week and eight hours per day. The jeans were washed in a washing machine using a detergent for delicates, and air dried. After four to six weeks of wear 74 to 78 % of the participants found the jeans pleasant to wear; application of the cosmetic via cosmetotextiles was perceived as being easier than a conventional cosmetic cream application by 93 % of the participants, a slight to strong improvement in the state of the thighs and their appearance was perceived by 69 to 74 % after four/six weeks of wear.
Figure 3: Microcapsulation as key technology
Enlarged version
Bringing perceptible cosmetic performance to textiles is a quite a challenge. To date, most cosmetotextiles have been launched with insufficient marketing communication and many consumers are still sceptical of the concept. Not surprisingly, the best commercial successes have been achieved via sales channels like teleshopping or catalogues which give more detailed information on the concept and the products. The progressive involvement of traditional cosmetics and fashion brands will further strengthen the credibility of the cosmetotextile concept. Indeed, cosmetotextiles have been identified by independent market analyst Datamonitor as a trend on the rise in its ‘Ten Trends to Watch in Packaged Goods in 2010’ report and France is funding research into cosmetotextiles as an innovative approach to create new opportunities and market segments for textiles.
Notes:
1) Skintex® is a registered trademark of Cognis GmbH.
2) This article was published in COSSMA, Issue 3, 2010, pages 22-25.
Authors
Dr. Raymond Mathis
Dr. Raymond Mathis, Director of Technology, Delivery Systems, Care Chemicals, focused on highly functional textiles, especially on the washing-resistant integration of microencapsulated cosmetic emulsions in textiles in the past ten years. Prior to that, he was head of development in the field of fiber lubricants and textiles additives over many years. Next to textiles as delivering cosmetics to the skin, delivery systems for classic cosmetics were added to his activities two years ago, aiming at increasing the efficacy of cosmetic active ingredients by means of various technologies.
Dr. Annette Mehling
Dr. Annette Mehling has been working for Cognis GmbH since 2001. She is part of the Product Safety and Regulations Department and is responsible for dermatological compatibility and efficacy testing. Dr. Mehling is a trained molecular biologist and obtained her PhD in microbiology at the University of Wuppertal. During her 4-year postdoctoral training at the Department of Dermatology, University of Münster, Germany, she was involved in research in the field of cutaneous immunology.
top