Chemical/Physical Properties
Palapreg P18-03 is an unsaturated polyester resin derived from maleic acid and glycol, dissolved in styrene. This resin has moderate viscosity and high reactivity.
Main Applications
Palapreg P18-03 is recommended for use in formulations with high-polymer solutions (such as Palapreg H850-01, H852-03,Palapreg H 1080-01, etc.) to produce parts with low protrusion and for Class A applications, as well as high-quality, low-shrinkage (H814-01) SMC/BMC parts.Formulations based on P18-03 are highly versatile, offering high surface quality, low delamination, and improved pigment dispersion. SMC formulations based on Palapreg P18-03 can be easily thickened with magnesium oxide.
Product Specifications at Delivery
| Properties | Range | Unit | TM |
|---|---|---|---|
| Viscosity, 23°C | 1680–1900 | mPa·s | 2013 |
| Color, Lico 200 | 0–100 | APHA | 2017 |
| Solid Content, IR | 64–66.5 | % | 2033 |
| Appearance | Clear | - | 2265 |
| Water Content | 0.06–0.10 | % | 2350 |
| Acid value, as received | 14.5–18.5 | mg KOH/g | 2401 |
| Gel time | 40–70 | seconds | 2261 |
| Curing Time | 80–120 | seconds | 2261 |
| Peak Temperature | 270–295 | °C | 2261 |
| Accelerated Thickening | 490,000–790,000 | mPa·s | 2,914 |
Viscosity: Reactivity determined
using the Z2/100/23°C method by adding 1 g of TBpB to 100 g of resin.
Typical values: Refractive index (23°C - TM 2150) = 1.5180 - 1.5210
Properties of Liquid Resin (Typical Values)
| Property | Value | Unit | TM |
|---|---|---|---|
| Density, 23°C | Approx. 1100 | kg/m³ | 2160 |
| Flash point | Approx. 33 | °C | 2,800 |
| Shelf life, unopened, in the dark, at 25°C | 3 | months | - |
Properties of unfilled resin (typical values)
| Property | Value | Unit | TM |
|---|---|---|---|
| Flexural Strength | 95 | MPa | ISO 178 |
| Flexural modulus | 3.6 | GPa | ISO 178 |
| Transverse fiber strain | 2.8 | % | ISO 178 |
| Tensile strength | 50 | MPa | ISO 527-2 |
| Tensile modulus (modulus of elasticity in the tensile direction) | 3.5 | GPa | ISO 527-2 |
| Elongation at fracture | 1.5 | % | ISO 527-2 |
| Heat Deflection Temperature (HDT) | 140 | °C | ISO 75-A |
| Glass Transition Temperature (Tg) | 185 | °C | DIN 53445 |
Properties of SMC Compression-Molded Parts (Typical Values)
| Property | Value | Unit | TM |
|---|---|---|---|
| Glass Content | 30 | % | - |
| Bending Strength | 180 | MPa | ISO 178 |
| Flexural modulus | 11.0 | GPa | ISO 178 |
| External fiber strain | 2.5 | % | ISO 178 |
| Tensile strength | 100 | MPa | ISO 527-2 |
| Tensile modulus (modulus of elasticity in the tensile direction) | 10.5 | GPa | ISO 527-2 |
| Elongation at fracture | 1.7 | % | ISO 527-2 |
| Impact Strength - Notched Specimen | 85 | kJ/m² | ISO 179 |
| Molding Shrinkage | -0.07 | % | DIN 53464 |
Typical starting formulation for SMC paste
| Component | Weight |
|---|---|
| Palapreg P 18-03 | 50 |
| Palapreg H 852-03 | 50 |
| TBpB | 1.5 |
| Calcium carbonate | 200 |
| Zinc stearate | 4 |
| MgO paste (35% MgO) | 2.5 |
Processing:
Palapreg P 18-03 is processed together with polymer resins to form LP-SMC and BMC. The ratio of Palapreg P 18-03 to the polymer solution depends on the type of polymer solution used and can be adjusted as needed.Depending on the mold size, it is recommended to add 300 to 600 ppm of hydroquinone to the system (calculated based on a heated melt solution of unsaturated polyester resin).