ART OF ENHANCING ACTIVE DELIVERY

“MICROENCAPSULATION”

What is microencapsulation?

In a relatively simple form, a microcapsule is a small sphere with a uniform wall around

active core material. The material inside the microcapsule is referred to as the core,

internal phase, or active , whereas the wall is sometimes called a shell, coating, or

membrane. It protects the inside core of actives from environmental conditions like

temperature, oxidation, degradation, volatilization etc. with time.

Why microencapsulation ?

The reasons for microencapsulation are countless. It is mainly used to increase the

stability and life of the active being encapsulated, facilitate the manipulation of the active

and control its liberation in an adequate time and space. In some cases, the core must be

isolated from its surroundings, as in isolating actives like essential oil extracts from the

deteriorating effects of oxygen, retarding evaporation of a volatile core, improving the

handling properties of a sticky material, or isolating a reactive core from chemical attack. In

other cases, the objective is not to isolate the core completely but to control the rate at

which it leaves the microcapsule, as in the controlled release of fragrances or drugs or

pesticides. The problem may be as simple as masking the taste or odor of the core, or as

complex as increasing the selectivity of an adsorption or extraction process. In

environmental sciences - pesticides, insecticides, bactericides, fungicides are needed to

be microencapsulated to minimize leaching or volatilization risks.

The other reason for microencapsulation lies in the fact that it is a perfect technique for

developing insecticides, fungicides and pesticides which are more environment friendly

and therefore more sustainable. An ideal insecticide, fungicide or pesticide is one - which

is very specific in activity against a target organism, is effective at low dosages and when

the action is over is quickly degraded in the environment. However the very idea of quick

degradation of the active in the environment works against its usage and that’s where

microencapsulation helps. Microencapsulation helps in targeted release of this ideal active

to the time or place where it is required most and then the active quickly degrades. Thus

microencapsulation brings about sustainability benefit in these applications. We have

seen typically that actives which are very effective and very stable in the environment e.g.

tin salts, DDT etc. start building up as environmental residues and eventually need to be

banned. Microencapsulation allows use of otherwise environmentally degraded actives in

a safe manner.

Benefits of Microencapsulation :

This technology is helpful to deliver

- long lasting effect of the active with a control release at a stage where it will have

the best effect e.g. fragrances on dry fabric after wash and not during wash only.

- reduced dosing frequency and amount needed of pesticides/insecticides.

- Slow release antibacterial, antimicrobial, antifungal, fragrance actives.

- Non leaking phase change materials coatings for automotive interiors or

construction/building.

- UV absorbers or reflectors for military applications.

- Slow release cooling agents, Insect repellents, thermochromic inks etc on a micron

scale.

- antimicrobials which it stops the growth of microbes on surfaces like fabric, paper,

wood, cardboard, carpet, curtain etc.

For the hospitality industry, microencapsulation allows us to deliver actives to fabric

surfaces which remain even after washing and tumble drying or to deliver actives which

last for a very long time like on surfaces near the pool or gardens which are prone to

humid/severe conditions. Thus we can deliver long lasting actives like fragrance or

essential oils to fabric surfaces eventually delighting our end consumers as well as deliver

antimicrobials to protect our staff’s health from unhealthy bacteria and fungus.

Microencapsulation helps deliver very effective low dosage antifungals to take care of

mildew and moulds on carpets and upholstery, neutralizing these microbes at source.

Types of Microencapsulation

Typically two types of Microencapsules are prevalent for various non-Food/pharma uses

1. Water Soluble Matrix type microcapsules : Here the active is embedded in the wall of

the capsule resembling a sponge structure Typical active loading achieved are of 40-55%.

It is a dry Powder with 30-80µ mean particle size. Release of active happens when this dry

powder comes into contact with water

2. Water Insoluble, Shell & Core functional microcapsules with high temperature (160-

250°C) resistance, pH resistance and leakage resistance. These give triggered release

through burst or diffusion. Temperature activation can be designed for specific

applications. Typical active loading achieved are of 80-95%. Mean Particle size range

between 5-15µ. They are typically delivered in a water dilutable slurry form which can be a

proprietary mix of surfactants, capsules etc.

Effort is not only required in making the best microcapsules suitable to the application but

also integrating these capsules into the final product which will be used e.g. shampoo,

liquid detergent or cationic ready to use format.

Applications and Uses of Microencapsulation :

In the use of product, the capsules get attached to fabric or fiber and gives burst release of

actives after friction, abrasion, rubbing, time being.

The applications and uses of micro-encapsulation are numerous. The mentioned below

are some of the most common ones.

• Textiles

Adhesives

• Fragrances

• slow release Antibacterial

• heat resistant Antifungal

• heat resistant /slow release Antimicrobial

• Thermochromic ink

• Phase change material

• Carbonless copy paper

• E-paper or e-ink

• Essential oils, Flavors and other volatile

bioactives for food or in Feed additives

• Insecticides, Pesticides and herbicides

• Powder perfume

• Scratch-n-sniff

• Insect Repellents

• Thermochromic dyes and inks

• Time release technology for pharmaceuticals

• Visual indicators and brighteners

• Pigments and Dyes

• Self healing coatings & paints

• Slow release Fungicide

• Slow release Antistatic agents

• Long lasting dry delivery of fragrances

• Fabric softener actives

• Hard surface cleaning actives

• Skin and/or hair conditioning agents

• UV protection agents

• Animal/vermin repellants,

• Flame retardants

• Temperature release (controlled release)

- Vineet Mital