CLEANING OR THE SPINNERETS FOR MELT SPINNING
TO clean spinnerets, you may choose one of the following methods which
we recommend:
1.Calcination: In automatic box type furnace, the spinnerets are heated
to 450～480℃. When temperature is over 480℃, a superheated steam will
blown out the flames to lower the temperature so that the spinnerets
can be prevented from being damaged.
2.Salts Bath: Formed by NaNO345%-NaNO245%-NaOH10% in mixture, salts
bath
acts as strong oxidant at its operating temperature, i.e., 450～500℃.
The polymer is decomposed to CO2 and H2O within 60 to 90 minutes.
After processed, remaining salts on spinnerets can be washed out by
hot water and oxide removed by thin nitric acid.
3.Procedyne Fluid Bed: At temperature of 450～500℃, aluminium oxide
powder is fluidified by hot air stream and scour the spinnerets. Polymer
is detached and decomposed. Carbon becomes CO. All these including
inorganic substances, such as TiO2, are discharged in the air.
4.TEG: First put spinnerets in boiling solution which contents NaOH(15～20%)for
2 to 3 hours to remove most of the polymer, then in TEG bath at 260～280℃
for about 12 hours. After cooled. spinnerets should still be washed
sequentially in alkaline solution, water and ultrasonic tank before
they can be dried and stored up.
This process can avoid overheat and is suitable for any type of stainless
steel, but needs rather long time.
5.Vacuum Calciner: Burning in low pressure and vacuum, most of the
polymer can be
decomposed. Remaining substances are washed out by water in the same
furnace. The whole
process can be automatically controlled and easily operated. |
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