Developing VOC-free formulation with microfibrillated cellulose
Anni Karppinen | August 29, 2017
Governments around the world are pushing industries to reduce their volatile organic compound (VOC) emissions. VOCs include very different type of chemicals but they may be dangerous to human health and therefore there is a common desire to reduce the use of them. Health effects vary from eye, nose and throat irritation to causing cancer.
The United States Environmental Protection Agency (EPA) lists the following sources of VOC in consumer use:
paints, paint strippers and other solvents
cleansers and disinfectants
moth repellents and air fresheners
stored fuels and automotive products
A lot of work has been done already to reduce the VOC levels in these products and the most important precaution is, of course, to follow the user instructions. However, the desire is to go towards totally VOC free formulations and there might be a role to play also for microfibrillated cellulose (MFC).
Paint and coatings industry has a high focus on VOC emissions and health effects since paints and varnishes are used all around us, meaning that many people are exposed to the emissions. Traditionally, many paints and coatings contain aliphatic and aromatic organic solvents, like xylene, toluene and mineral spirits. Even if these solvents work well in technical sense, the health and environmental concerns have led to search of alternative solutions. Kwaamba (2013) mentions four technologies that can help to reduce or replace VOC: water-borne systems, high-solid solvent-based systems, powder coatings and radiation-cured finishes.
MFC shows VOC reduction potential in paints and coatings by enabling the use of water-borne systems where it earlier was not possible as well as replacing some of the VOC agents still present in the water-borne systems. One of the challenges restricting the use of water-borne systems is that they tend to dry significantly faster than their solvent-borne counterparts, resulting in challenges in actual painting. MFC increases the open time of the formulation partly due to the water holding capacity but also due to its ability to prevent skin formation. This means that by using MFC it is possible to move to water-borne systems where it was not possible earlier.
Pesticide industry is another industry which is aiming to reducing VOC emissions. VOCs coming from the pesticides affect the environment slightly differently since they are used outside. When VOCs react with NOx (different oxides of nitrogen coming from, for instance, exhaust gases) ground-level ozone is formed. California Department of Pesticide Regulation lists different ways to reduce VOC emissions from pesticides: adopting more integrated pest management practices, timing of the application, reducing amount of pesticides applied and alternative pesticide formulations. MFC can aid the development of the two latter ones.
MFC has shown to enhance the effect of pesticides when added to the spray tank (see my earlier blog post on this topic). This can help to reduce the amount of pesticide applied by ensuring that the applied product works optimally. Moreover, MFC can replace hazardous, VOC emitting substances used as adjuvants today.
Pesticides formulations vary from different types of powders and granulates to liquids. For example, emulsifiable concentrate (EC) often causes more VOC emissions than powders or suspension concentrates (SC). MFC can be used to stabilize SCs and help to develop water-based formulations with low or none VOC.
Generally, moving towards water-based formulations in any industry reduces or eliminates VOC emissions. MFC, being an effective and often multifunctional rheology modifier, can help to develop water-based formulations that have improved properties compared to the existing technology.