SELVOL POLYVINYL ALCOHOL AS A PVC DISPERSING AGENT
Polyvinyl alcohol (PVOH) has long been utilized as a primary dispersing agent in polyvinyl chloride (PVC) suspension polymerization. The use of specific PVOH grades can influence the droplet stability & particle morphology, contributing to the properties of the PVC particles, e.g. porosity, bulk density, and thermal characteristic.
Selvol 540 is the most popular grade used as a primary dispersing agent in PVC suspension polymerization. Its continued demand over the past decade highlights the consistent, high quality product the PVC industry has come to depend on.
See Table 1.
In addition to Selvol 540, Sekisui Specialty Chemicals also offers Selvol E605, Selvol E635 and Selvol E640 as primary dispersing agent options. These Selvol PVOH grades provide unique properties needed for PVC suspension polymerization via optimized degree of hydrolysis and particle size. See Table 2 for an example of SELVOL E635 in a K-67 PVC formulation.
| Units | SELVOL 540 | SELVOL E605 | SELVOL E635 | SELVOL E640 | |
|---|---|---|---|---|---|
|
Degree of Hydrolysis |
Mol % |
87.0 – 89.0 |
78.5 – 82.0 |
78.5 – 81.5 |
78.5 – 81.5 |
|
Viscosity (4% solution) |
cPs |
45.0 – 55.0 |
4.0 – 5.0 |
32.0 – 38.0 |
36.0 – 42.0 |
|
Ash |
Wt % |
0.50 Max |
0.50 Max |
0.50 Max |
0.50 Max |
|
Volatiles |
Wt % |
5.00 Max |
5.00 Max |
5.00 Max |
5.00 Max |
Selvol Polyvinyl Alcohol as a PVC Dispersing Agent
TABLE 2: SELVOL E635 EXPERIMENTAL DATA – “K-67” TYPE FORMULATION
| Unit | SELVOL E635 | Market Standard A | Market Standard B | |
|---|---|---|---|---|
|
Mean Particle Size |
µm |
162 |
159 |
157 |
|
48 mesh |
% |
100 |
100 |
100 |
|
60 mesh |
% |
99.0 |
99.8 |
99.8 |
|
100 mesh |
% |
54.7 |
54.2 |
67.1 |
|
200 mesh |
% |
4.6 |
6.4 |
6.2 |
|
Bulk Density |
g/ml |
0.571 |
0.566 |
0.577 |
|
Porosity |
% |
16.2 |
17.1 |
16.7 |