We specially produce STMMA copolymer resin series mold materials for foam lost casting, including STMMA, STMMA-FD expandable copolymer resin beads, and they are mainly used to produce castings for valves, pipings, car fittings and various machinery fittings
Compared with EPS, STMMA series expandable copolymer resin beads have much excellent casting performances:
Reducing carbon defect of castings;
Reducing carburization defect on surface of steel castings;
Reducing smoke carbon;
Improving surface finish of castings
|
|
EPS |
STMMA-FD |
STMMA |
|
Composition |
(C8H8)n |
|
-(C5O4H8)-m |
|
Carbon content |
92% |
82% |
63% |
|
Temperature of foaming |
80~85 ℃ |
85~95 ℃ |
95~105 ℃ |
|
Temperature of decomposition |
912℃ |
900℃ |
700℃ |
|
Gas evolution of 900℃ |
600ml/g |
700ml/g |
900ml/g |
|
Casting temperature(for gray iron) |
1500~1460℃ |
1480~1450℃ |
1450~1400℃ |
|
Residuum after foamed mold decomposing |
65% |
30% |
4.5% |
|
Shrinking percentage of foamed molds |
0.3~0.8% |
0.2~0.4% |
0.1~0.3% |
|
Rate of finished casting products(for boxes and motor housings) |
80~92% |
≥93% |
≥98% |