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Skip to content Expandable copolymer resin STMMA - raw materials for the foam molds manufacturing in the production of lost foam casting technology (LFC) – is a copolymer of polystyrene (30%) and methyl methacrylate (70%) with functional additives that quickly reduce the molecular weight of polystyrene at elevated temperatures.
Depending on STMMA beads size, the following product types are distinguished: STMMA-1, STMMA-2, STMMA-3, STMMA-3А, STMMA-4 (see specifications).
STMMA copolymer resin is designed specifically for the of foam-pattern manufacturing using LFC technology (full-mold casting) for casting products from aluminum, copper alloy, grey iron, nodular iron, alloy steel, mild steel and stainless steel.
The select of beads size shall be according to the min. thickness of the casting wall, used to be 1/10 of it. For example, you could choose the 700 µm size beads if the casting’s thinnest wall is 7mm. If the casting needs a high precision, it can also choose the next small class.
| Product | Suitable for castings with minimum thickness of |
|---|---|
| STMMA-1 | 6,0-9,0 mm |
| STMMA-2 | 4,5-6,0 mm |
| STMMA-3A | 4,5-6,0 mm |
| STMMA-3 | 3,5-5,0 mm |
| STMMA-4 | 2,5-3,5 mm |
Store in tightly closed original packaging at a temperature from +5°C to +15°C.
Store in a cool, dry, well-ventilated area, away from heating appliances, strong oxidizing agents and alkalis. Protect from direct sunlight, moisture, and freezing.
Guaranteed shelf life - 3 months.
Storage over the date specified on the label does not necessarily mean the product is unusable. In case if store more please check the properties of product before use.
Steel drums 25kg.
Steel drums 125 kg.
Detailed instructions are given in the relevant product safety data sheet. It can be provided upon request.
| Parameter name and measure unit | Standard |
|---|---|
| Appearance | Opaque milky white beads |
| Chemical formula | -(C5O4H8)-m |
| Content of volatile substances (by weight), %, min. | 7,0 |
| Humidity, %, max | 6,0 |
| Bead size (maximum range), microns: | |
| STMMA-1 | 600-900 |
| STMMA-2 | 450-600 |
| STMMA-3A | 400-550 |
| STMMA-3 | 350-500 |
| STMMA-4 | 250-350 |
| Density, g/dm3: | |
| STMMA-1 | 18-20 |
| STMMA-2 | 19-21 |
| STMMA-3A | 20-22 |
| STMMA-3 | 21-23 |
| STMMA-4 | 23-26 |
| Carbon content, % | 63 |
| Foaming temperature, ℃ | 95-105 |
| Decomposition temperature, ℃ | 700 |
| Gas evolution of 900℃, ml/g | 900 |
| Casting temperature(for gray iron), ℃ | 1400-1450 |
| Foam-pattern density, g/dm3 | 20 |
| Percent of residues, % | 4,45 |
| Shrinking percentage of foamed molds, % | 0,1-0,3 |
| Rate of finished casting products(for boxes and motor housings), % | ≥98 |
