MEHRAN UNIVERSITY Of ENGINEEING And TECHNOLOGY JAMSHORO

Department of Textile Engineering

PRESENTATION TOPIC:

Microencapsulation and its applications in Textile

Presented by: Kashif Khan Khuhro (12TE88)

Structure and Mechanism2

CONTENTS

Constituents and Benefits3

Introduction1

Application in Textiles5

Techniques4

Conclusion6

Introduction…….

History

The origins of the process of microencapsulation lie in the pharmaceutical and paper industries of the 1940s. However, the textile industry started introducing encapsulated products, in its articles between 1980 and 1990.

The pharmaceutical industry has long used microencapsulation for the preparation of capsules containing active ingredients.

During the past 10 years this approach has been explored widely by the agricultural, food, cosmetic, and textile industries.

What is MICROENCAPSULATION……???

Micro-encapsulation is a process in which tiny particles or droplets are surrounded by a coating to give small capsules many useful properties.

Micro-encapsulation may also be defined as the process of surrounding or enveloping one substance within another substance on a very small scale, yielding capsules ranging from less than one micron to several hundred microns in size.

The potential size range of the microcapsules produced is enormous,

with typical diameters being between 2 and 2000 µm.

Capsule walls are typically 0.5-150 µm thick, although walls measuring less than 0.5 µm can be achieved.

The proportion of core material in the capsule is usually between 20 and 95% by mass.

The substance that is encapsulated may be called the core material, the active ingredient or agent, fill, payload, nucleus, or internal phase.

The material encapsulating the core is referred to as the coating, membrane, shell, or wall material .

Microcapsules may have one wall or multiple shells arranged in of varying thicknesses around the core.

Microencapsulation involves the production of microcapsules which act as tiny containers of solids. Microcapsules have walls less than 2 μm in thickness and 20–40 μm in diameter is useful in fiber applications.

Fig. Microencapsulation: Paraffinic PCM core material individually with a hard polymeric shell.

Structure of a Microcapsule

Microcapsules basic structures. (Courtesy of Ronald T. Dodge 2009)

A close view of Microcapsules…

MECHANISM ….

How it Works…..???

Microencapsulation can have two distinct objectives. On one side, to block the substance within the

microcapsule, necessarily rigid, when the diffusion of a product is not desired.

The second objective is the progressive liberation of the active ingredient within the microcapsule which, in this case should have a more fragile wall. This second option is the most used in case of the functional or active textiles.

CONSTITUENTS & BENEFITS ……..

Microcapsules may contain… A perfume, scents A cosmetic product(moisturizer, freshener, toner, etc.) An odor absorbing product Insect repellents A combination of ingredients(e.g., perfume+ bactericide) X chromes (pigments whose color changes to X environment) Dyes or ink PCM (Phase Change Materials) Vitamins, Nutrients, .. Drugs, pharmacological products, … Bacteria, virus, ADN, … Enzymes Living cells. Others …

Benefits of Microencapsulation……….

Protection of unstable, sensitive materials from their environments prior to use.

Better processability Self-life enhancement by preventing degradative reactions

(oxidation, dehydration). Controlled, sustained, or timed release. Safe and convenient handling of toxic materials. Masking of odor or taste. Controlled and targeted drug delivery. Handling liquids as solids

Techniques to apply on Textiles…….

In the polymer On fabric by padding In a coating Spraying Transfer print Injecting into the yarn

APPLICATION IN TEXTILES …….

1-PHASE CHANGE MATERIALS The intention of microencapsulation of phase-change materials is to

reduce the influence of extreme variations in temperatures. Phase-change materials are materials that change the aggregation

from solid to liquid within certain range of temperature.

In this way the thermoregulation of clothing is achieved and the constant temperature is provided.

PCM capsules were first applied by the NASA in the early 1980s for use in space suits. Today these kinds of microcapsules are applied to different materials, vests, snowsuits, blankets, mattresses etc

2-Fragrance finishes

Numerous trials have been made at adding fragrances directly to fibre and fabrics, but the aroma vanished after one or two wash cycles.

By the use of microencapsulation fragrances are able to remain on fabric for a longer period of time.

Microcapsules may contain essential oil flavors like lavender, rosemary, pine and other for the effect of aromatherapy. This is used mainly to help with insomnia, headache, and to prevent bad odor.

The Slovenian producer Aero Celje has developed microcapsules with essential oil that were applied to shoe sock.

Vitamins and moisturizers are also applied to all types of textile substrates, including hosiery and baby wears.

3- FIRE RETARDANTS Fire retardants applied to textile products often cause the

reduction of softness. To conquer these problems microcapsules with fire retardant

core were developed. They are applied to fabrics used in military applications like tentage.

4- PHOTOCHROMIC AND THERMOCHROMIC MICROCAPSULES (COLOUR-CHANGING TECHNOLOGY)

The application of photo chromic and thermo chromic microcapsules can be found in textiles like product labeling, medical and security applications.

One of the colour changing systems changes colour in response to temperature, this is thermo chromatic and the other changes colour in response to UV light, the photo chromatic.

Today even microencapsulated thermo chromatic dyes are produced that change colour at specific temperature - in response of human contact.

5- ANTIMICROBIALS

Bacteria are often related to the notion of bad smell or disease and in textile industry the loss of useful properties of fabric often refers to microbiological decay of fibers.

To prevent this problem the importance and demands of antimicrobial finishes continue to grow, especially for textiles for medical and technical use.

To realize these functionalities, nanotechnology offers a lot of new Possibilities. Antimicrobial finishes can be applied to textiles also by microencapsulation.

The release of active substances of microcapsules with antimicrobial agent is slow or sustained.

Textiles with antimicrobial finishes are known in the market by different names, like Bacterbril, Biofresh, Terital, Trevia Bioactive, Amicor etc

6- COUNTERFEITING

Microencapsulation can be used to deal with the problem of illegal copying in high added value textiles and in branded and designer goods with providing a hidden yet clear marking system.

Microcapsules applied to label contain a colour former or an activator.

By the use of UV light or a solvent, microcapsules break open, the content is released, colour is developed and in this way detection is achieved

INTERESTING ASPECTS !!!

CONCLUSION

The possibilities of application of microcapsules to textiles discussed are just some of the most interesting.

Today there is almost no field where microcapsules would not be presented.

Encapsulation became a very powerful tool, because it is invisible and comes to life at the slightest touch.

REFERENCES

1- G. Nelson (2002) Application of microencapsulation in textiles. International Journal of Pharmaceutics 242 (2002) 55-62

2- http://www.celessence.co.uk/micro.htm (2000) 3- M. Leskovšek et al. (2005) Microcapsules in Medical and

Hygienic Products. Textilec 48 (2005) 37-42 4- http://pro.wanadoo.fr/euracli/en/textile.htm (2000) 5- M. Kukovič et al. (1998) Microcapsules for Textile Industry.

Tekstilec 41 (1998) 225-230 6- http://www.flok.ru/news/FLOCK%20News_7.2006_e.pdf

(2006) 7- Nelson, G., Wales D.S., Sagar, B.S., 1991. Treating Materials.

European. Patent, EP 0511 258 B1. 8- Nelson, G., 1991. Microencapsulation in textile coloration and

finishing. Rev. Prog. Color 21, 72–85.