Innovations resulting from technological advancements represent the best strategy for success in the increasingly competitive textile industry. Smart textiles are part of daily life .Recently fragrances /scents have become available that can be formulated in to fibers. The powerful influence of a perfume has been shown in consumer moods, as its presence on the fabric can influence the shopping behavior and buying decisions. Researchers tracking the home textile segment have found out that consumers spent more time in the jewelery section of a departmental store, when it was suffused with a pleasant aroma than when it was un scented. The influence of odors on purchasing and consumer behaviour demonstrated further the distinct effects and hedonic value of scents and fragrances in human beings.

Principle and Applications of Micro Encapsulation:

Micro encapsulation is a process by which very tiny droplets or particles of liquid or solid material are surrounded or coated with a continuous film of polymeric material. These micro capsules have a number of benefits converting liquids to solids, separating reactive compounds, providing environmental protection and improved material handling properties.

Textile manufacturers are demonstrating increasing interest in the application of durable fragrance to textiles. Micro encapsulated phase change materials (or micro PCMs) are used for temperature regulation in certain products, such as wearing apparel, footwear, foam and bedding materials. It consists of encapsulated paraffin-wax substance which absorbs and releases heat in order to maintain a regulated temperature. For example, if the coated capsule were used in a skier jacket, the paraffin wax would initially absorb the skiers body heat and store it until the body temperature drops from the outside environment; at which time, the heat is released giving warmth to the skier and keeping the temperature regulated for his/her comfort.

Textiles with phase change materials (PCMs) are used in a number of products and applications from apparel, underwear, socks, accessories and shoes to bedding and sleeping bags. PCMs can even be found in specialty items, such as antiballistic vests, automotive, medical or special industrial applications, where warmth and energy play a role. Phase change materials {PCMs} incorporated in the fabric, interact with the skins temperature to provide a buffer against temperature wings.PCMs are materials that can absorb, store, and release heat while the material changes from solid to liquid and back to solid. This stage is called Phase Change. Water changing from solid {ice} to liquid is a classic example of this phenomenon. During these phase changes large amounts of heat are absorbed or released.

Micro encapsulation of phase change materials

Phase Change Materials (PCMs) consist of an encapsulated substance with a high heat of fusion which absorbs and releases thermal energy in order to maintain a regulated temperature within a product (such as clothing, upholstery, packaging and building materials). They can be tailor made either microcapsule or macro capsule forms. Micro encapsulation is the process of capturing small amounts of phase change materials in a sheet material, so that the phase changes materials are permanently enclosed and protected. The protective polymer shell is durable and designed to with stand textile production methods used in fiber, yarn spinning, weaving knitting and coating applications.

There are a number of technologies that can be used to give materials new characteristics. One of these is the introduction of tiny microcapsules containing certain products in to fabrics. These capsules release their contents under certain conditions .For example, a causal wear can be equipped with micro capsules containing a natural product such as Menthol. When the capsule burst, menthol is released, keeping the insects and bugs at a distance.

Micro encapsulation is a process in which tiny particles or droplets are surrounded by a coating to give small capsules with many useful properties. In a relatively simplistic form, a microcapsule is a small sphere with a uniform wall around it. The material inside the microcapsule is referred to as the core, internal phase, or fill, whereas the wall is sometimes called a shell, coating, or membrane. Most microcapsules have diameters between a few micrometers and a few millimeters. Many micro capsules, however, bear little resemblance to these simple spheres. The core may be a crystal or a suspension of smaller microcapsules. The micro capsule may even have multiple walls.

Applications on Textiles

Micro encapsulation is one of the novel methods of getting functional finishes on textiles. The capsules do not have any affinity to fabrics, acrylic binder is used to fix the capsules for finish durability. Fixation is done at 15-160 d for 2- 3 minutes, to make the components of the binder cross link together and tightly fix capsules on the fabric. During curing, the aroma inside capsule, however, can be lost through quick evaporation. and swelling to escape or break the capsule. The loss from the capsule can seriously reduce the amount of aroma on the fabric and decrease the durability.

An aroma capsule finished fabric can last for roughly 20-25 normal washes. To avoid the loss of the aroma, UV resin can be used to fix capsules because the resin can be cured under UV light at low temperatures in seconds .During the UV curing, the amount of aroma lost is limited and ensures higher durability of the finish. An aroma capsule finished cotton fabric treated by a thermal curing process can only bear 25 wash cycles. To avoid the thermal process, an UV resin can be used to fix capsules because the resin can be cured under UV light at low temperatures in seconds .During UV curing the amount of lost aroma is limited, which ensures a higher durability of the finish. Fabric finished with selected aroma capsule and UV resin and cured under the optimal conditions can with stand up to 50 standard washing cycles.

Other potential applications include, insect repellents, dyes, vitamins, antimicrobials, phase change materials and in specific medical applications. Any area in the industry could benefit from micro encapsulation technologies. on textile applications of micro encapsulations are many, one of them is carbonless copy paper, which is an alternative to carbon paper, used to make a copy of an original, handwritten document with out the use of any electronics. Carbonless paper works in a fairly simple way. It consists of sheets of paper that are coated on the bottom and or top with micro encapsulated dye. The back of the first sheet is coated with micro encapsulated dye. The top of the middle of the middle sheet is coated with the dye. The lower most sheet is coated on the top surface with the clay with no coating applied to the back side.

Upon putting pressure from the point of the writing instrument, the micro capsules rupture and breaks and spills their dye. Since the capsules are very small, the print obtained is very sharp and accurate. The capsule compositions are generally 80-85% capsule core, and 15% capsule wall. The particle size ranges from 1-10 microns with a mean size of 2-3 microns. The core material has a combination of high performance solvents and dyes, and breaks, when used along side with a suitable activator. The capsule wall is an inert and a stable polymer or plastic.

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