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N°
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Answers
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1.
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How should the resin and hardener
be mixed?
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Always keep accurately to the mix
ratios specified for mass on the technical
data sheets. If the cross-linking agent is overdosed that ruins the
electrical and mechanical properties, and in extreme cases the product
does not harden at all. Owing to the different densities of the
components, mixing in volume ratio may result in the
deterioration of the properties of the end-product, and in extreme
cases the product does not harden at all.
The cross-linking agent should be flown on the side of the tank and
added to the resin this way. The two materials should be mixed
perfectly, preferably with a low rpm mixer mounted on an
electric drilling machine, and the mixing head should always remain
under the surface of the liquid so that no air is taken into the
mixture. Mixing can be carried out in other ways, too e.g. with manual
mixing, the important aspect is that the mixture should be completely
homogeneous, and no bubbles should be taken into the material. The
mixed material should be poured into another empty pot, and mixed again
there.
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2.
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How much material should be mixed
at once?
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Mix only an amount that can
be utilized within the processability time.
The mixed resin and cross-linking agent starts to react immediately,
and release heat meanwhile. In case of larger masses, this heat cannot
leave, and that makes the reaction even faster, hence in case of mixing
a larger amount, it is worth keeping it in a tank with a larger surface
or cool the tank from outside Since reaction heat accelerates
the reaction, the same material binds more quickly if the amount or the
layer thickness is larger and all other conditions are the same.
The processing time of filled systems is longer than that of unfilled
systems (of the same quantity).
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3.
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What can the resin mix be diluted
with?
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No thinner should be
added to the mixture. If the mixture does not seem to have the adequate
viscosity for a given purpose, choose another system.
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4.
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How can cross-linking be
accelerated?
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Bonding time can be decreased by
heating at 40-60 °C. The chemical reaction accelerates owing to the
heat, so adequate care should be taken!
Bonding time cannot be accelerated with a higher
amount of cross-linking agent. In extreme cases the impact can be
opposite, the system cannot cross-link, and remains 'sticky'.
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5.
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How does temperature influence
processability time and system properties?
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Even temperature and low humidity are
important for the production of high quality products. If it is
possible, work with a resin kept at room temperature, since the
viscosity of the too cold resin increases, hence the perfect
homogenization with the cross-linking agent, good spreading and space
filling are all more difficult.
+10 °C temperature increase processability time decreases to its
half (compared to room temperature)
-10 °C temperature decrease processability time doubles (compared
to room temperature)
Do not use the product below the temperature given in the technical
data sheet, since its surface may remain sticky and it does not bond
completely
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6.
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What can the system be dyed with?
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The EPOREZIT two-component epoxy
resins can be dyed with coloring pastes or powder pigments.
Never use water based coloring agents with these systems, since water
inhibits cross-linking.
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7.
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What filling materials should be
used for epoxy resins?
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Mineral fillers (dried sand, silica
flour, talc, aerosil etc.) can have beneficial impact on both
processing and the properties of the end product depending on the
application
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8.
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What impact the filling material
has on the properties of the resin mix and the end product?
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In case of applying filling materials,
heating up decreases during cross-linking, the processability time of
the mixed material increases, shrinkage decreases, the unit cost of
same size pieces is lower. The compression strength, hardness, Martens
heat resistance of the end product improves, and water absorption will
also decrease. However, other mechanical properties deteriorate to a
given extent, and the mixture of larger viscosity is difficult to
exclude bubbles from and more difficult to process. The amount of added
filling material is optional, can even be a multiple of the amount of
resin
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9.
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What can a mold be cleaned with
and how long?
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In case mixing is done in a
polyethylene pot, the remaining material can be snapped out with a
mechanical impact. Other pots, tools, brushes, rollers all have to be
cleaned with an EPOREZIT tool cleaner or an organic solvent, such as
acetone immediately after usage. In case of product EPOREZIT AKVA 100,
the tools can be cleaned with water. If the resin is already bonded,
the tools can no more be cleaned.
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10.
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What can reactive diluents be
used for?
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The EPOREZIT reactive thinners are
epoxy compounds that contain no additives and can be used for diluting
and modifying epoxy resins.
They react with EPOREZIT cross-linking agents in the same way as epoxy
resins do.
Their application field is mainly the modification of epoxy resins, as
more diluted, less viscous resins can be produced using these thinners.
Not only does the viscosity of the resins diluted with reactive thinner
change but also their reactivity, hence in case of the reaction with
the cross-linking agent the reactivity of the diluted resin and not the
original resin should be considered.
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11.
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What safety instructions have to
be applied during usage?
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The general chemical industrial safety
instructions concerning epoxy resins and cross-linking agents have to
be obeyed. The resins are maximum slightly irritant, while the cross
linking agents are irritant and can cause skin problems on sensitive
parts such as hand, arm and eyelid. The vapors of the cross-linking
agents strongly irritate the eyes and mucous membranes, hence good
ventilation has to be provided at the workplace. Take care that the
material does not spatter in the eyes both in case of mixing and
pouring..
It is compulsory to wear safety glasses and adequate safety gloves. If
the material gets in contact with skin, it should be washed off with
plenty of water. Skin must not be cleaned with a solvent, since the
solvents can help the quick absorption of cross-linking agents.
If work is interrupted or finished, hands should be washed thoroughly
and greasy protective hand creme should be applied. In case of contact
with the eyes, the material should be washed with a plenty of water
immediately, and rinse with a physiological salt solution. The general
protective rules should be obeyed when processing epoxy resin products.
Provide adequate ventilation.
The cross-linked system has no harmful impact on the environment or on
health, as far as we know.
Detailed information can be found in the material
safety data sheet.
If skin inflammation or eye injuries occur despite the above mentioned
measures, medical help should be sought
Eating, drinking and smoking are prohibited during working!
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12.
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How can bubble formation be
avoided?
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The resin and the cross-linking agent
should be mixed with a low rpm mixer, and the mixing
head should always remain under the surface of the liquid so that no
air is taken into the mixture. Bubble formation can be minimized this
way.
The resin is heated up to 80-90°C and you should wait until the bubbles
leave. If a filling material is also used, first add the dry filling
material to the resin and then exclude bubbles. The cross-linking agent
should be mixed into the resin free from bubbles and cooled down to
room temperature. The resin mixed with the cross-linking agent
should not be heated again since the warmer system
is firstly more flowable and less viscous but the reaction accelerates
and processing time decreases suddenly.
Bubbles can be excluded by applying vacuum or de-aerating
additives (for further information, please contact our
representatives).
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13.
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How long can the epoxy resins and
cross-linking agents be stored?
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Resins can be kept in dry places, in
closed tanks, possibly in covered warehouse areas for several years.
The cross-linking agents applied with them can be stored for 1 year.
Some cross-linking agents are especially sensitive to the humidity in
air, hence if only a little material is left in an opened pot, it is
practical to put it into a smaller tank and close it properly. The
material of the storing pot can be metal, plastic or glass.
At lower temperatures the cross-linking agents can crystallize, but if
they are warmed (up to 50°C) a little before usage, this can be ceased
(reversible process). Before usage, always wait until the product cools
down to room temperature.
Both product components should be kept away from water, humidity and
radiant heat.
Our guarantee on the products is valid for 1 year
starting from the date of purchase.
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