Method (ASTM)
Specific gravity D-792-64-T 1.19
Water absorption D-570-63 0.3%
Burning rate D-635-63 30 mm/min
Residual monomer   20% Max: (Wt)
Light transmittance,    
Total D-1003-61 93%
Refractive Index, Nd D-542-50 1.49
Critical angle    
(/\=5893A)   42`15`
Tensile strength    
at rupture D-638-64 T 760kg/cm
Elongation at rupture D-638-64 T 4.5%
Modulous of elasticity D-638-64 T 28.000kg/cm
Compressive strength
at yield D-695-63 T 1,260kg/cm
Impact strength    
charpy unnothched   0.48kg-m
Izod milled   0.4 ft-lbs per in. Of notch
notched D-256-56  
Rockwell Hardness D-785-62 M100
Coefficient of thermal    
expansion (-30 to 30°c) D-686-44 6x10`cm/cm/°c
Thermal   5x10° Cal/Sec/Cm/°C/cm
conductivity C-177  
specific heat (-20 to 80°C)   0.35 Cal/gm °C
Heat forming temperature   140-180 °C
Heat distortion temperature    
2°C/Min.At 264 p.s.i D-648-56 100°C
Maximum recommended    
continuous service temperature   85°C
Volume resistivity D-257-61 >10 15 ohm-cm
Dielectric strength D-149-64 20 KV/mm


Available Sizes
915x1830 mm (3' x 6')
1220x1830 mm (4' x 6')
1000x2000 mm
915x2440 mm (3' x 8')
1220x2440 mm (4' x 8')
915x1830 mm (3' x 6')

Thicness Tolerance Chart
1.5 TO 3.0 mm +/- 0.1
4.0 TO 6.0 mm +/- 0.2
8.0 TO 15.0 mm +/- 0.4


Storage & Handling
Sheets must not be placed in contact with heating coils, radiators, hot water, steam pipes or any other source of heat, Unpacked sheets should be kept on edge in angled frames.
Horizontal storing of sheets should be done carefully, covering each sheet with a piece of cloth to avoid scratches, without over hanging.

SPI sheets are masked by bleached craft paper on both sides to avoid scratching, during storage & handling. If the surface is scratched, proper polishing agent must be used while buffing & hand polishing. It is recommended that 1% of soap solution should be used for sheet cleaning.