The raw materials required for the production of kraft paper are:
-The main component, namely used scrap paper, both from
within Thailand and from abroad are
- Long and short-fibre pulp. Long fiber pulp improves
strength to the paper and short fiber pulp
improves smoothness.
- Various chemicals are added to give the paper properties such as water proofing.
Manufacturing process have 2 steps:
1) prepare paper pulp
2) produce paper
Prepare paper pulp step
To produce corrugating board:
-
It begins with used scrap paper, which is pulverized
to separate out the fibers in a pulp solution
- During this stage, whatever cannot be pulverized such as wire and string is removed from the process.
- The liquid pulp is then sent through a separator to
extract all minute, light-weight objects, such
as staples, plastic and foam. After these solid objects
have been eliminated, the liquid pulp
is still not clean, and must pass through a machine
to remove other contaminants, such
as ink and asphalt, by means of heat-induced molecular
displacement.
- The resulting clean pulp is then stored in a pulp
tank, which is controlled for density, pressure,
temperature, and acid- base content. Various chemicals
are introduced at this point to prepare
the liquid stock for conveyance to head boxes.
To
produce liner board :
-
The surfaces of liner board require different types
of kraft paper, for which the proportion of
long and short fibers differs according to the specifications
of each type.
- Both kinds of fibres are pulverized until they separate
in to solution. This process is meticulously
controlled to ensure the highest possible strength and
firmness of the finished product.
- The liquid pulp is then stored in another tank, which
is also controlled for density, pressure,
and temperature. Chemicals are likewise mixed in to
prepare the liquid stock for delivery
to its own head boxes for the production of surface-quality
kraft paper.
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