Fragrances, microencapsulated

Macro-coating is used mainly to stabilise fragrances or transform them from liquid to free-flowing solid powder. Microencapsulation or nanoencapsulation is the process of enclosing a substance inside a miniature capsule. These capsules are referred to as microcapsules or nanocapsules. The substance inside the capsule can be a gas, liquid or solid. The capsule wall can consist of various materials, such a wax, plastic or biopolymers like proteins or polysaccharides. 

Applications of microencapsulation in other industries are numerous. The best known microencapsulated products are carbonless copying paper, photosensitive paper, microencapsulated fragrances, such as scent-strips (also known as snap-n-burst ), and microencapsulated aromas ( scratch-n-sniff ). All of these products are usually prepared by gelatin-acacia complex coacer-vation. Scratch-n-sniff has been used in children s books and food and cosmetic aroma advertising. Microcapsules are also extensively used as diagnostics, for example, temperature-sensitive microcapsules for thermographic detection of tumors. ... 

Bone, S. Vauttrin, C. Barbesant, V. et al. Microencapsulated fragrance in melamine formaldehyde. 

Chemical companies are interested in the development of innovative system solutions, that is, new functional materials in which known molecules are integrated to show new effects. Flavor and fragrance companies are interested to protect and precisely release their valued molecules (the payload ). The polymer industry demands encapsulated curing agents and encapsulated reactants. These are just three examples, out of many, that show that microencapsulation is mainly used for the purpose of protection and controlled release. Since at least a decade, therefore, traditional low-volume markets for microcapsule-based products are expanding to include fine chemicals, adhesives, inks, fragrances, toners, sealants, and detergent manufacturers. ... 

Microencapsulation companies, including chemical makers, flavor and fragrance houses, and specialist firms, use competing technologies to manufacture encapsulated functional materials using either chemical or physical techniques. 

Further progress can be easily envisaged. For example, attempts to create perfumes based on suspended capsules go back to the early 1970s. Now formulation in water of sol-gel-entrapped perfumes of tunable scent to avoid skin irritation becomes possible. Stabilized natural fragrances replacing toxic synthetic musks are also forecasted herein. In particular, sol-gel microencapsulated essential oils will replace nonbiodegradable musks as a consequence of the chemical and physical stabilization of nice fragrances that thus far could not be widely commercialized due to weU-known poor chemical stability. 

The enzymes and scented oils added to detergents and cleaning agents are expansive raw materials. However, since only a small proportion of the fragrance adhered to the laundry, most of it is washed down the drain unused. Microencapsulation has proven to significantly increase effectiveness in this respect. 

In relation to detergent ingredients, different microencapsulation technologies are often used for fragrances and flavors. Coacervation and spray drying are mentioned in various patent applications (see example of coacervation in Ref 139 and spray drying in Ref 140). In the case of bleach active substances, microencapsulation of TAED using a polycondensation process is described in Ref 141, and a coacervation process for the encapsulation of PAP is mentioned in Ref 142. In both cases, the use in liquid applications is intended. 

Customer-based production of formulations (besides emulsions) based on a package system with an incorporated static micromixer [19] Microencapsulation in microreactors (e.g. fragrances) [25-28] Screening of cream formulations [17]... 

Microencapsulation by spray-drying is a low-cost commercial process which is mostly used for the encapsulation of fragrances, oils and flavors. Core particles are dispersed in a polymer solution and sprayed into a hot chamber (Fig. 1.15). The shell material solidifies onto the core particles as the solvent evaporates such that the microcapsules obtained are of polynuclear or matrix type. Very often the en-... 

Controlled or targeted release is the most common apphcation of microcapsules. Microencapsulation is an ideal tool to effect and achieve a desired delay of the active core until the correct stimulus is encountered. Most microcapsules are extraordinarily stable and show a great retardation of the encapsulated substances. Fragrances, aromas, drugs, enzymes, cosmetics and even pharmaceutical formulations (vitamins, drugs) are encapsulated for delivery from textiles at a specific time, rate, or situation. The encapsulated substances can either be released at once... 

Microencapsulation is a necessity for active ingredients of poor stability such as odor agents. Some of the biggest challenges in this field are controlled release of fragrances and their long-lasting perceptions (Pena et al., 2012). 

Fei, X., Zhao, H., Zhang, B., Cao, L., Yu, M., Zhou, J., Yu, L., 2015. Microencapsulation mechanism and size control of fragrance microcapsules with melamine resin shell. Colloids and Surfaces A Physicochemical and Engineering Aspects 469, 300—306. 

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