is converted into Shellac either by traditional hand made
process or comparatively modern machine made process.
Seedlac is converted into Shellac either by traditional hand
made process or comparatively modern machine made process. Hand
made shellac is produced by properly blending Seedlac into long
narrow cloth bag and heating one end over charcoal fire and the
other end is attached to a windless and is gradually twisted.
The heat produced by the charcoal fire melts the lac which is
forced out through the cloth by pressure. The molten lac is
scraped out and drawn into sheets manually and left to dry. This
process requires considerable manual skill and long experience.
The traditional hand made grades are Lemon No.1, Lemon No.2,
Standard One, TN Superfine etc. Hand made shellac is mostly
exported to U.S.A., Germany, Japan etc. The impurity varies from
0.75% to 1.5%.
MACHINE MADE SHELLAC…….
Is produced in two different ways- one is the heat process where
the same principle as in the case of hand made shellac is
applied and the second is solvent process where pure shellac is
extracted from Seedlac by suitable solvents. Under heat process
the separation of pure lac is achieved by melting Seedlac by
steam heat and squeezing the soft molten lac through filter my
means of hydraulic presses. The molten lac is then stretched by
means of rollers into long continuous sheet which is broken into
pleces to form the machine made Shellac under heat process. This
shellac has an impurity content varying from 0.5 to about 1%.
There are various grades under heat process machine made
shellac. The most popular being TN, Lemon and Orange. These
grades are exported to practically all lac consuming countries.
Under solvent process wax and impurities are practically
Completely removed by dissolving the seedlac in a suitable
solvent, usually, chilled industrial alcohol. The solution is
then filtered through fine cloth and the alcohol is recovered by
boiling the solution. The molten shellac is then stretched to
the required thickness on a roller. The product does obtained is
known as Dewaxed Shellac. The most popular grades being Dewaxed
Orange, Dewaxed Lemon, Dewaxed Garnet etc. Highly sophisticated
grades of dewaxed and Decolourised Shellac can be produced by
this method by adding activated carbon as the decolouring agent.
The impurity is around 0.2%. Dewaxed or Decolourised Shellac are
imported mostly by the advanced countries like U.S.A., Germany,
U.K., Italy, France etc.
USES OF SHELLAC
Due to versatility of lac resin, it finds innumerable uses both
in industries fields. On the stand point of industrial uses of
shellac one or more of the following properties are of great
dissolves in a wide variety of alkaline or rapidly drying
alcoholic solvents but is resistant to a number of other
solvents particularly hydrocarbons.
film shows excellent adhesion to a wide variety of surfaces,
possessing high gloss, hardness and strength.
is powerful bonding material with low thermal conductivity
and a small coefficient of expansion. Its thermal plasticity
and capacity of absorbing large amounts of filters are
electrical properties include high dielectric strength, low
dielectric constant and characteristic freedom from
is resistant to the action of ultraviolet rays.
of the main uses of shellac in different fields are :
coating – As under coat, primer, sealer French, Polish,
Leather dressing, Fruit Coating etc.
– Flexographic ink, Waterproof ink, Photo engraving.
– Stiffening of hats.
& Pharmaceuticals – Hair lacquer, coating for Enteric
pills, Dental base place.
– Grinding wheels, Rivet & Plaste sealer.
– Micanite, Insulating Varnish.
– Dry mounting tissue paper, protective varnish.
– Paper varnish, playing cards.
– Stiffening agent, surface finish.
– gasket cement,sealing wax, pyrotechnic Optical Cement.