Green Adhesives

By PALANIRAJ

GREEN initiative in a company has become a way of life across all the business spectra. Greener materials increase the efficiency of resources such as energy, water and materials used by the adhesive manufactures, which in turn reduces the impact on human health and environment. Effective use of greener materials has paved the way for: ?Reduced operating cost by using less energy and water which leads to increase in production ?Adherence to air quality standards which in turn improves the public and occupant health standards ?Less environmental impact Volatile organic compound (VOC) comes from different sources like raw materials, energy emission and harmful substances. VOC's have high vapor pressure and low water solubility. VOC's are known to cause sensory irritation and central nervous system symptoms.

What's So Green about New Adhesives?

Green adhesives can be defined in several different ways and the most common definitions are ?Adhesives manufactured from sustainable raw materials ?Adhesives manufactured in through an environment-friendly process ?Adhesives which have low VOC emission Several adhesives manufacturers in the recent past have developed green adhesives as part of compliance with environmental regulations and social responsibilities.

Green Raw Materials

Demand for green adhesives is rapidly growing in the developing countries as the living standards and the disposable income are on the increase. In the developed regions like North America and Western Europe, adhesive demands closely follow the Gross Domestic Product. Among the green raw materials that are being used for these alternative adhesives are rosin, starch and soy.

Rosin.

Pine chemicals are used in producing plant sterols, turpentine, resin acids or rosins and fatty acids. They are renewable and naturally available materials derived from pine trees. Rosin and its derivatives account for the largest consumption for pine chemicals market. Rosin has major uses in adhesives, printing inks, coatings, surfactants, rubber, paper products and chewing gums. In adhesives application, the packaging and book binding segments account for major consumption of rosin, followed by pressure sensitive and construction adhesives. Due to high demand for supply of styrene-isoprene-styrene (SIS) polymers in the pressure sensitive adhesive market, the manufactures are considering alternatives like styrene-butadiene-styrene (SBS) and styrene-isoprene-butadiene-styrene (SIBS). This current trend increases the demand for the pine chemical like rosin ester and polyterpene resin which gives better performance and equal compatibility with their alternate polymer system. The compatibility of rosin resins with polymers used in aqueous adhesives makes them well suited for these new systems. As new or modified polymers continue to be introduced, new waterborne resins will be developed to meet the challenge. Some pine chemicals are used in radiation-cured systems, but the demand for this system is very low as compared to the overall demand. Pine chemicals, like rosin ester and terpene phenolic resins; have been used in radiation-cured acrylic adhesives.

Starch.

Due to its biodegradability and renewability, the usage of starch in commercial adhesive compounds minimizes environmental damages. Starch finds its major application in modifying chemicals into thermoplastic materials. Starch undergoes bio-degradation through molecular breakdown by enzymes attack on the glucosidic linkages between sugar groups. The biodegradability of the polymer increases with the starch content. Approximately 60% of starch content is required for significant material breakdown. Normally most of the starch-based biodegradable polymerHighsnobiety Style