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ANTI-STATIC FLOOR FINISH TECHNICAL APPLICATION BULLETIN
Anti-Static Floor Finish Composition
The application and maintenance procedures and equipment for
applying ElectraGlaze anti-static floor finish is basically the same as for
standard floor finishes. Anti-static a/k/a electro-static discharge (ESD) floor
finishes made by any manufacturer, have a different chemical structure which
requires that special attention be paid to certain details when they are being
applied and maintained.
To provide static dissipation, anti-static finishes like ElectraGlaze contain a
special active ingredient. This active ingredient is not readily compatible with
standard floor finish polymer chemistry. Producing a quality ESD finish requires
that a finely tuned balance be achieved between having a sufficient
concentration of the active ingredient to provide effective ESD properties,
while avoiding an unacceptable level of the side effects inherent when
incorporating anti-static compounds into finishes. These side effects can
include increased water sensitivity, reduced gloss, extended drying times and
slipperiness. The cause of these side effects is the active ingredient’s
tendency to absorb humidity present in the environment into the finish film.
These hydrophilic properties help anti-static floor finishes to dissipate static
charges. The consideration is that factors that inhibit regular floor finishes
from drying and curing, like cool floor temperatures, high air temperatures
coupled with high humidity and heavy coat application, also effect anti-static
floor finishes, but to a much greater extent. This means that additional care
and time must be taken when applying anti-static floor finishes.
Anti-Static Floor Finish Application Considerations
In order to achieve effective static dissipative properties, a sufficient amount
of active ingredient must be present in the floor finish film. To obtain static
dissipation on anti-static vinyl composition tile or anti-static epoxy floors, a
minimum of two coats of ElectraGlaze is necessary. On regular vinyl composition
or other non anti-static flooring, a minimum of three coats of ElectraGlaze is
required. In order to function correctly, both immediately after application and
over time, the anti-static active ingredient must effectively bond to the
polymer chain. Once a floor finish is applied, film formation occurs in two
phases.
The first phase involves the evaporation of the water from the finish. Most
floor finishes, ESD and regular, contain between 75% and 84% water, which must
leave the finish film before the second curing phase can start. The second
phase, sometimes referred to as the glass transition phase, occurs after the
water has evaporated and the co-solvents/plasticizers have reached a high enough
concentration to initiate cross-linking of the various polymers used to make up
the finish. It is during this curing phase that the anti-static ingredient
becomes bonded to the polymer chain.
During both of these phases there are a number of environmental conditions and
application factors that impact both evaporation rates and the curing of the
polymer.
1. Air Circulation-moving air holds more moisture than stagnant air, so
although positive air circulation is beneficial under any circumstance it
becomes critical in higher humidity conditions.
2. Floor Temperature-the optimum floor temperatures for
effective evaporation and curing of both regular and ESD finishes is 65-75o F.
Floor temperatures at either extreme can have a significant negative impact. At
less than 50o F many polymers will never achieve the glass transition phase,
never cure and will display adhesion failure, powdering, lack of gloss and
streaking and mop marks. At excessively high temperatures, greater than 85o F,
floor finishes can flash dry at the interface between the floor and bottom of
the finish film and may not adhere properly. When ever possible, adjustments
should be made to the environmental controls to bring floor temperatures a close
to optimal as possible. If adjustments can’t be made, cooler floor temperatures
will require additional drying and curing time.
3. Humidity-humidity conditions are an important factor in the
drying and curing of any finish, but can have a critical impact on the
performance of ESD finishes. The ideal application humidity level for ESD
finishes is 40% relative humidity or lower. 40% relative humidity is also the
level at which ESD finishes provide optimum static dissipative properties. As
previously mentioned, the second curing phase of finishes starts when sufficient
water has evaporated and the co-solvent/plasticizer levels reach a high enough
concentration to initiate cross-linking of the polymers. The challenge with ESD
finishes is that this is also approximately the point at which the anti-static
active ingredient reaches a high enough concentration to start absorbing
atmospheric humidity. This creates a conflicting set of chemical reactions which
results in ESD finishes being much more sensitive to humidity levels and drying
times than standard floor finishes. At humidity levels higher than 60% ESD
finishes can take an extraordinarily long time to cure, as much as 24 hours per
coat, so when possible, it is best to simply avoid applying ESD finishes under
these circumstances.
4. Drying Times-most standard vinyl composition tile finishes
will generally dry and have cured sufficiently to allow additional coats to be
applied within 20-60 minutes depending on humidity conditions. Because of their
chemistry ESD finishes take substantially longer. United SCP recommends that no
more than 3 coats be applied in an 8-hour period, under positive drying
conditions. A minimum of 2 and preferably 4 hours drying time should be allowed
between coats. Adverse drying conditions will require allowing even longer
drying times between coats.
5. Coat Thickness-due to ESD finish’s particular chemistry they
should be applied as thinly as possible. Coverage rates should be approximately
2000 ft2 to 2500 ft2 per gallon. Heavy applications will take longer to dry and
cure, and will increase the potential for experiencing short and longer term
performance problems.
Symptoms of and Procedures for Correcting Misapplication
ESD finishes are prone to displaying the same symptoms of
incomplete drying and curing that regular floor finishes are. These symptoms
include increased friction or drag when applying successive coats. Mop marks or
streaking after the finish has dried but has been unable to cross link and cure,
a lack of or inconsistent gloss characteristics and inconsistent adhesion that
ultimately results in powdering of the finish off the floor.
What Causes an Oily Film:
A condition that is specific to ESD finishes is directly related
to the anti-static active ingredient they contain. This condition occurs when
multiple coats of ESD finishes are applied without sufficient time for the
finish to cure and the anti-static ingredient to bond to the polymer chain. In
these circumstances, the un-bonded active ingredient which has a lower specific
gravity than the other floor finish components, floats to the surface and forms
a greasy sometimes slippery feeling layer on the surface. Correcting this
problem requires that the surface be scrubbed with a low speed (175-300 Rpm)
buffing machine or automatic scrubber equipped with red buffing or blue cleaning
pads and a solution of 8-10 ounces of United SCP ElectraClean per gallon of warm
or hot water. The solution that will now contain the dissolved anti-static
ingredient should be vacuumed or mopped up. The floor should then be coated with
a thin application of United SCP ElectraGlaze and allowed to cure for 24 hours
before being put back into service. This procedure will generally restore the
film so that it complies with the EOS/ESD Association’s S20/20 recommendations
of a 1x107 to 1x109 Ohms/Cm2 @ 40% relative humidity, resistivity specification.
In extreme circumstances so much active ingredient may have migrated from the
finish film and been removed by scrubbing that a second coat will be required to
restore appropriate resistivity readings.
Allow 72 hours curing time after the last coat of finish before washing with
ElectraClean. If possible allow 5 days curing time before spray buffing or burnishing with
ElectraShine. |
