Polyester Glass Laminates
This material is made up of fiberglass filaments impregnated with polyester resin, strengthened with heat and pressure to form solid and tough plates with high rigidity levels.
It is a thermosetting material and it is unsuitable for reforming or remolding.
It is better than phenolic products (finished with paper or cotton fabric support) as regards rigidity and arching resistance while slightly superior as regards heat resistance.
This type of insulating plate is suitable for use in the manufacture of collar plates, cotter pin slots for traction engines, collar plates for rotating field coils, panel spacers, busbars, connecting rods for various types of switches, boards for electric panels, as well as critical applications which require its superb resistance and dimensional stability.
Its good weather resistance makes it suitable for being used as insulating boards in rural transformers.
It satisfies ASTM D – 1532 standard in grades
– GPO – 1 General purpose
– GPO – 2 Flame resistant general purpose
– GPO – 3 Flame resistant and arching resistant
Chemical Resistance Chart
| Composite | % | ºC |
| Transformer oil | 100 | 110 |
| Acetic acid | 10 | 70 |
| Acetic acid | 50 | 50 |
| Fatty acids | 100 | 110 |
| Citric acid | 100 | 100 |
| Nitric acid | 5 | 50 |
| Phosphoric acid | 80 | 90 |
| Sulfuric acid | 25 | 90 |
| Sulfuric acid | 50 | 70 |
| Tanic acid | 100 | 90 |
| Methanol | 100 | 20 |
| Ethanol | 100 | 20 |
| Aqua ammonia | 5 | 60 |
| Calcium hydroxide | 525 | 40 |
| Sodium hydroxide | 10 | 80 |
| Sodium hydroxide | 25 | 50 |
| Hydrogen peroxide | 30 | 60 |
| Sodium hypochlorite | 15 | 70 |
| Carbon monoxide | — | 110 |
| Sodium bicarbonate | 100 | 100 |
| Acetic acid* | 100 | 100 |
| Sodium cyanide | 100 | 100 |
| Sodium phosphate | 100 | 100 |
| Potassium nitrate | 100 | 100 |
| Potassium permanganate | 100 | 100 |
| Zinc chloride | 100 | 100 |
Comparative Properties of Different Grades
| Property | Unit of measure | Polyester glass cloth | GP0 – 1 | GP0 – 2 | GP0 -3 |
| Density | G/cm3 | 1.78 | 1.70 | 1.75 | 1.75 |
| Tensile strength | Kg/cm2 | 1800 | 1200 | 1400 | 1500 |
| Flexural strength | Kg/cm2 | 2600 | 1400 | 1700 | 1700 |
| Compression strength | Kg/cm2 | 2600 | 1400 | 1800 | 1800 |
| Impact strength | Kg cm/cm | 80 – 90 | 70 – 80 | 110 | 110 |
| Module of elasticity | Kg/cm2 x 103 | 210 | 190 | 190 | 200 |
| Dielectric strength | kv/mm | 12 – 14 | 12 | 12 | 14 |
| Power factor | —- | 0.020 – 0.040 | 0.02 | 0.02 | 0.03 |
| Dielectric constant | —- | 4.5 | 4.0 | 4.2 | 4.6 |
| Resistance to flame | seg* | 20 | — | 20 | 20 |
| Arching resistance | seg* | 70 | 70 | 70 | 120 |
| Humidity absorption | % | 0.3 | 0.4 | 0.4 | 0.4 |
| Temperature range | —- | >B <F | >B<F | >B<F | >B<F |
Thickness and Tolerance Chart
| Nominal Thickness (mm) | Tolerance (mm) | Nominal Thickness (mm) | Tolerance (mm) |
| 0.5 | +- 0.03 | 7 | +- 0.30 |
| 0.6 | +- 0.03 | 7.5 | +- 0.30 |
| 0.7 | +- 0.05 | 8 | +- 0.30 |
| 0.8 | +- 0.05 | 9 | +- 0.30 |
| 0.9 | +- 0.07 | 10 | +- 0.40 |
| 1.0 | +- 0.10 | 11 | +- 0.40 |
| 1.5 | +- 0.10 | 12 | +- 0.40 |
| 2.0 | +- 0.12 | 13 | +- 0.40 |
| 2.5 | +- 0.12 | 14 | +- 0.40 |
| 3.0 | +- 0.15 | 15 | +- 0.50 |
| 3.5 | +- 0.15 | 16 | +- 0.50 |
| 4.0 | +- 0.15 | 17 | +- 0.50 |
| 4.5 | +- 0.15 | 18 | +- 0.50 |
| 5.0 | +- 0.20 | 19 | +- 0.50 |
| 5.5 | +- 0.20 | 20 | +- 0.50 |
| 6.0 | +- 0.20 | 21 | +- 0.50 |
| 6.5 | +- 0.20 | 22 | +- 0.50 |
For thickness greater than the ones mentioned in the chart above, tolerance increases at 0.1 mm per 8 mm of increment of laminate thickness.
Maximum measurements: 1600 x 950mm