B)
MICA POWDER
Mica Powder in various forms is obtained by grinding/breaking
mica scrap, which is a slow, costly and extremely complicated
process, because of the scrap being tough and having a plate like
structure. Meticulous care and precaution has to be taken so that
there is no deterioration of its natural brilliance, colour and
properties.
1)
MICA FOR WELDING ELECTRODES
Muscovite dry ground mica is well recognised for use in mild steel
rutile based welding electrodes. In the manufacture of welding
electrodes a core of steel wire is coated uniformly with a 'flux'
comprising mica as a lagging compound. Mica is added to the 'flux'
with which welding electrodes are coated as binders, extrusion
agents and pigments to aid slag formation, weldpool protection
and arc stabilisation. The mica coating provides two distinct
types of protection to the welding rods. Firstly, it serves in
forming a fusible slag and a good seal at the fusion zone on the
arc. Secondly, it resists the action of heat, gaseous and other
surrounding atmospheric oxidization. In fact, it is the nature
of mica coating that largely determines the quality of a welding
electrodes.
2)
MICA FOR GYPSUM PLASTER BOARDS
Muscovite dry ground mica is light in weight, non-combustible,
free flowing, chemically inert, resilient and non-abrasive. It
have good thermal insulation properties and an excellent characteristics
for sound absorption. Low shrinkage and coefficient of expansion,
good dimensional stability, temperature stability, and extremely
low water absorption are some of its additional outstanding features.
All these properties makes mica an ideal product for use as a
filler in light-weight fire-resistant pre-fabricated gypsum wallboard
slabs and panels for building constructions, in place of asbestos,
where thermal insulation and acoustic properties are of particular
importance.
3)
MICA FOR WALLBOARD JOINT CEMENTS
Dry ground muscovite mica is effectively used a cost-effective
filler and surfacing agent in wallboard joint cement compounds
to fill the joints between panels of wallboards, as well as, in
the finished coating of ceilings in building constructions, because
of its many functional and morphological surface characteristics.
In this particular application, mica acts as a reinforcing pigment
reducing penetration into porous surfaces, improving mixing and
trowelling properties of jointing cements. High heat resistance,
excellent mechanical and thermal strength, low moisture absorption,
high surface leakage resistance, unusual chemical resistance and
non-hygroscopic properties are some of the distinctive mica properties
which makes it an useful ingredient for use in the above applications.
4)
MICA FOR ACOUSTIC PRODUCTS
Muscovite mica powder is widely used as a filler in non-asbestos
acoustic products for treatment of automobile under-bodies and
noise protection systems because of its functional, morphological
and surface characteristics. The addition of mica in acoustic
compounds improves its material properties significantly, such
as, improve heat and UV resistance, increase tensile and flexural
strengths, reduce isotropic shrinkage and permeability, enhance
the dielectric and insulating properties, better surface properties,
etc. In fact, Mica is a unique mineral which offers the multiple
advantage of noise and vibration absorption, reduces flammability,
adds low temperature impact resistance, high thermal stability
and multi-directional lateral reinforcement to composite plastic
polymer compounds such as superior quality and excellent dimensional
stability than mica.
5)
MICA FOR ASBESTOS-FREE BRAKE LININGS
Mica has an outstanding electrical, thermal, mechanical and chemical
properties. High heat resistance, excellent mechanical and thermal
strength, low moisture absorption, high surface leakage resistance,
unusual chemical resistance and non-hygroscopic properties are
some of the most distinctive properties of mica. Mica particles
are stronger than iron and are not brittle like other inert inert
material. It serves to reinforce, stiffen, harden and strengthen
the product and prevent microscopic ruptures, reduce warping,
lower thermal expansion and conductivity. During the mixing process,
the use of mica helps to achieve a more homogeneous mix. Due to
platy nature and surface characteristics of mica, it tends to
lock together under compression during wet or dry, cold or hot
processes to form an effective plateform for the matrix of other
materials in the formulation. As such, the benefit of mica for
use as friction materials for asbestos-free brake linings, brake
shoes, clutch discs, etc. is well recognised.
6)
MICA POWDER FOR RUBBER & TYRE APPLICATIONS
It is suitably used as an anti-blocking, anti-sticking and anti-friction
agents between the inner rubber and castings of rubber tyres for
aeroplanes, automobiles and motor bikes. It is primarily used
as a dusting agent and mold lubricants to prevent massing and
adhesion of the rubber compounds during vulcanization and acts
as a separating factor for the cores of the outer sheath. Besides,
it prevents movement of sulphur while permitting air and moisture
to escape during curing and helps create a uniform pore structure
that leads to improve resiliency and reduced shrinkage.
MICA
MANUFACTURING CO. PVT.LTD.
3C,
Camac Street, P.O.Box
9052,
Kolkata 700 016 INDIA
Tel: +91-33-40663006
E-mail
:mica@micamaf.co.in / mmc@micamafco.co.in