Silica Coating
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The hydrophobicity of a surface is determined by the contact angle. The higher
the contact angle the higher the hydrophobicity of a surface. Surfaces with a
contact angle < 90° are referred to as hydrophilic and those with an angle >90°
as hydrophobic. Some plants show contact angles up to 160° and are called
super-hydrophobic meaning that only 2-3% of a drop's surface is in contact.
Plants with a double structured surface like the lotus can reach a contact
angle of 170° whereas a droplet’s actual contact area is only 0.6%. All this
leads to a self-cleaning effect.
Dirt
particles with an extremely reduced contact area are picked up by water
droplets and are thus easily cleaned off the surface. If a water droplet rolls
across such a contaminated surface the adhesion between the dirt particles,
irrespective its chemistry, and the droplet is higher than between the particle
and the surface]
Paint sealants compared to Coatings
Automotive paint surfaces
are porous and contain microscopic peaks and valleys, much like the profile of
a mountain range. These irregularities are known as capillary structures; there
may be millions of these defects per square inch. Contaminants such as fine
dirt, minerals, and pollutants are drawn into the voids where they are
extremely hard to remove.
Paint sealants are synthetic products
designed for long-term paint protection and easy application. They are composed
mainly of amino functional polymers, which last longer than any natural wax and
are highly resistant to the elements. Synthetic liquid waxes are another way of
describing paint sealants. The main benefit of a paint sealant is their
durability compared to a wax, polymer-based sealants will last anywhere from 3
to 6 months.
A coating is applied to a clean
surface that surface takes on properties that are virtually identical to
hardened glass. It is chemically inert and will not react with the base
material. In other words, dirt will not bond to the treated surface, thereby
reducing soiling and organic staining. Acid rain and other chemical compounds
easily wash off, significantly reducing the hydroscopic nature of surfaces
exposed to industrial or environmental pollution.
Hydrophobic surface [: The requirements for a
self-cleaning hydrophobic surface are a very high static water contact angle θ,
the condition often quoted is θ>160°, and a very low roll-off angle, i.e.
the minimum inclination angle necessary for a droplet to roll off the surface] [1]
Repellant [: able to repel a particular thing;
impervious to a particular substance]
The lotus effect [:
refers to self-cleaning properties that are a result of very high water
repellence (super- hydrophobicity), as exhibited by the leaves of the lotus
flower] Dirt particles are picked up by water droplets due to the micro
architecture on the surface, which minimizes the droplet's adhesion to that
surface
Silica Coating consist of four chemicals
– Silicon (Si), Siloxane (H(OSiH2)n OH), Silane (SiH4 ) and Silazane(a
silicone compound), once formulated they become Silicon
Dioxide (SiO2) they are marketed under various brand
names: AQuartz is an inorganic
silica / silicon dioxide, G|techniq is an
inorganic silicate crystallization compound, Nanolex is an inorganic,
solvent-based nanostructure coating, Opti-Coat™ is
a polymer-based (Si02) coatings. DuPont's
SupraShield™, PPG's Optech™ and CeramiClear™
are all inorganic silica automotive paint coatings.
Be cognizant that there are many glass
coats in the market today and many of them can all be traced back to one or two
suppliers
Silica coating are a clear liquid in a
molecular form that is held in a polymer solvent carrier system. This silica is
aerobic (hardens on contact with air) and becomes glass. Multi-chemical component
coatings interlace on a molecular basis and form an extremely durable protective
layer on the paint surface provided they are applied properly. These coatings
are chemically inert and are highly resistant to a range of chemicals both acid
to Ph. 2.0 and alkali to Ph. 13.5 acid,
they also offer resistance to solvents, and they are very durable and capable
of obtaining a surface thickness of Mils (µ (microns) to be verified
When a silica coating is applied to a
clean surface, that surface takes on properties that are virtually identical to
hardened glass. It is chemically inert and will not react with the base
material. In other words, dirt will not bond to the treated surface, thereby
reducing soiling and organic staining.
Acid rain, bird excrement and other
chemical compounds easily wash off, significantly reducing the hydroscopic
nature of surfaces exposed to industrial or environmental pollution.
The paint surface is porous and contains
microscopic peaks and valleys, much like the profile of a mountain range. These
irregularities are known as capillary structures. Contaminants such as fine
dirt, minerals, and pollutants are drawn into the voids where they are
extremely hard to remove. Capillary structures also provide microbes and
bacteria with an excellent place to grow and multiply.
A silica coating fills the capillary structures,
which produces a smooth flat hydrophobic surface. (A hydrophobic surface is one
that repels moisture.) In contrast, a hydrophilic surface is one that absorbs
moisture. The potential of a surface to absorb or repel moisture is based on
many factors, including: temperature, relative humidity, material homogeneity,
and static electricity. Surface roughness is also a major factor; the rougher
the surface, the higher the spreading rate or attraction for water. The
smoother the surface, the more repellent it is to moisture.
Some formulations of Liquid glass
contain titanium dioxide for extra shine without affecting durability. These
micro-particles of titanium dioxide reflect light of specific wavelengths,
producing an instant luminous shine and gloss. Titanium dioxide is sensitive to
photocatalyzation and produces traces of active oxygen when exposed to ultra
violet (UV) radiation. This effect helps the coating to prevent the attachment
of contaminants to the paint. This means that, in most instances, environmentally
damaging cleaning chemicals are not needed.
Silicosis happens by breathing the dust
particulates of 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
Modesta P-01A and BC-04 Nano-Titanium Glass coating - is definitely a worthy investment if your vehicles
appearance is important to you. An advanced and very unique glass coating, it
forms a highly durable, clear hard glass layer on automotive paints. BC-05
produces a deep shine and helps to protect the paint from all kinds of damage
including wash-induced damages, scratches, oxidation, sap, watermarks, salts,
acids and even permanent ink and paints. Its strong water-repellent properties
also promote the self-cleaning (Lotus effect).
Used stand-alone as a sealant, BC-05 produces a unique candy-like gloss.
If combined with the P-01A primer this effect is even deeper as the layers of
both products are combined to a single coat. It can be applied even to the most
advanced and sophisticated paints, such as Nissan Scratch Shield, Lexus’
self-restoring coat and Mercedes ceramic paint. Durability is claimed to be in
excess of 10 years.
Product Application
Use the appropriate personal
protection equipment (PPE) an approved mask (Consult the current 3M
Respiratory Selection Guide for additional information or call 1-800-243-4630
for 3M technical assistance) nitrile gloves and safety glasses as a
minimum
My preferred application method is to
use base coating (P-01A) applied with a rotary machine polisher and apply the
coating with a spray gun as I feel this gives a consistent thickness and
coverage. The coating can be applied with a micro fibre towel but the major
disadvantage of this type of application is the coating dries and solidifies to
glass, which means you need 5- 8 towels that will be discarded after use.
Drying / Curing
Use of infra-red lamps is highly
recommended
Allow 24 hours on a moisture / dust free
environment
Maintenance
Using a specially formulated product
like Optimum No Rinse (ONR) by using 1 oz. of ONR to 2 gallons of water, when using a rinse
bucket, there is no need to add ONR to the second bucket. However, you should
wring the towel well after rinsing so that you do not dilute the wash bucket. This will help to
effectively clean your coating and it rinses away easily without leaving behind
gloss enhancers or other surfactants.
This is an ideal coating maintenance shampoo
Optimum Opti-Mitt is a soft, nonabrasive
8 Inch Foam Wash Mitt designed to work with ONR to remove grime without
scratching. The porous foam absorbs dirt and road oil to prevent paint marring.
The coarse yellow foam is excellent at cleaning wheels. Use the Opti-Mitt every
time you wash your vehicle for safe, swirl-free washing.
Summary
Silica coatings offers superior
durability, hydrophobicity, surface hardness and scratch resistance, resistance
to environmental contaminants and works in a similar way to a clear coat in
providing ultra violet (UV) and heat radiation protection without colour change
(yellowing) or oxidation and easier maintenance, simply rinsing with plain
water results in a clean surface without loss of gloss. I think these products
will have a profound impact and radically change auto detailing
Bibliography
1.
Royal Society of Chemistry (RSC) Library & Information Centre
2.
Glossary of Chemical Terms - Faculty of Chemical Technology
3.
Basic Concepts of Nanotechnology, History of Nano-Technology,
News, Materials and Potential Risks
4.
Lotus-inspired nanotechnology applications, B. Karthick1 and Ramesh Maheshwari
5.
SpecialChem4 Polymers
6.
Macromolecular Chemistry and Physics
7.
European Coatings
Handbook 2nd Edition, by Brock, Groteklaes, Mischke
8.
Bayer Material Science, Automotive eNewsletters (Coating, Adhesives and
Specialties)
The information in
this article is based on the current status of the technical development as
well as our experience with the products.
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