Friday, 27 March 2015

Silica Coatings: Protection from Potential Health Hazards

Wear appropriate personal protective clothing to include: Safety glasses, Hearing and Respiratory protection

Silicosis happens by breathing the dust particulates of silica (glass), which cut and scar the lungs, causing damage, which results in diminished lung capacity. So where does the silicon dioxide enter into this equation as a safe product to breathe when applied as a spray?
Liquid glass is actually a mixture of caustic soda, quartz sand, and water are prepared in a mixing tank, then fed into a reactor, where steam is introduced. The reaction is (n SiO2 + 2 NaOH → Na2O•nSiO2 + H2O). Sodium silicate is spherical silica in a liquid state, which essentially means ‘liquid glass’ crystals which are smooth and round instead of sharp and pointed.
Because there are no sharp edges to damage lung tissue it is relatively safe to breath. But why would we think it is safe to fill our lungs with round glass any more than with jagged sharp glass particles? Do the lungs have the ability to process and get rid of the ‘spherical’ shapes through the blood stream?
Is ‘liquid silicon dioxide’ really ‘colloidal silica,’ or is it ‘sodium silicate’? Silicon dioxide = SiO2 and Sodium silicate = Na2SiO3. Colloidal silica is simply the liquid spherical shape of silicon dioxide while sodium silicate is silicon dioxide with an added salt element (Na). Both products are derived from the second most abundant element on Earth – sand.
I would strongly suggest you do not breathe it in but use the appropriate personal protection. If you were to examine the urethane clear coat with high-performance electron- microscope, you would see lots of fissures or micro holes. Nano sized silica glass particles penetrate these fissures to form a mechanical anchor with the clear coat, creating a durable finish that won't fracture
Respiratory Protection (N95): Materials such as aluminium oxide (Aluminium oxide is on EPA's TRI list if it is a fibrous form) or silicon carbide (Nuisance particulate-Accumulation in lungs) used in polishes and compounds, and powdered fillers Crystalline silica (polishes and compounds) poses a serious inhalation hazard because it can cause silicosis and Isocyanate clear coat residue represent a hazard to your lungs and may cause respiratory distress.
The reliability of any respiratory is dependent on proper selection, training, medical screening, and respirator maintenance. Use a NIOSH-approved half face respirator equipped with a combination filter cartridge should be worn while using them
Consult the current 3M Respiratory Selection Guide for additional information or call 1-800-243-4630 for 3M technical assistance
Any problems that may become apparent are mostly due to the solvents that encapsulate the silica particulates, the most often used solvent / carrier system is a dilute isopropyl alcohol or ethanol water solution. Obviously there are no problems with water and other VOC-free solvents.

When using IPA/ethanol based products in an unventilated environment there is the risk of drowsiness or of becoming lightheaded, but that is a factor of the solvents used not the Silica particles - it's usually the steams of the solvents that cause these symptoms, Be cognizant the particles remain on the surface as the solvent evaporates - they are not in the steams.

I hope the above article was informative. By having some understanding of the ‘What’ and ‘Why’ as well as the ‘How’ along with a little science to help you understand how the chemicals we use react, you can achieve the results you desire safely.

Questions and/ or constructive comments are always appreciated

Copyright © 2002 - 2012 TOGWT® (Established 1980) all rights reserved

No comments:

Post a Comment