| Abnormal phenomena |
|
Solution |
| Glomerate occurs in PVA
solution or solution in yellow |
| 1. Not be soaked before dissolving or
feed into the hot water directly
2. Not agitate in a timely manner
3. Temperature raising speed is too fast
4. The dissolving temperature in
early stage is too high |
|
| 1. Soak at room-temperature
for 30-60m before dissolving
2. Agitate while feed material
3. Raise temperature slowly,
prolong the dissolving time properly
4. The dissolving temperature
of completealcoholysis product
is not lower than 98? |
|
| The concentration of pva is
too low or too high |
| 1. Fed water is excess or skimpy,
or added PVA is skimpy or excess
2. The type or specification
of PVA is impropriety |
|
| 1.Add PVA or water to suitable
concentration
2.Change PVA |
|
| Foam mass occurs
when dissolving PVA |
Temperature is too high, or it
is raising speed is too fast.
|
Control the speed of raising
temperature,drop the temperature
, add adequate defoamer or keep
the PVA solutionholding for defoaming |
| After dissolving for a long time,
there is undissolvable grain still |
PVA contains trace insoluble ingredient. |
| Filter the dissolved PVA(120 mesh) |
|
