Polycarbonate Compatibility - Part II

 ANSI/EIA-564-1992 Validates Polycarbonate Compatibility

                                                         Figure 2 - Left                                    Figure 2 - Right

Test Procedure

Five EIA-564 specified stress levels can be required while the specimens are undergoing oven conditioning upwards to four temperatures levels. The polycarbonate specimens are first annealed and placed into strain jigs (Figure 2-left). The agent or material under consideration is applied or fabricated to make intimate contact with the polycarbonate specimens. The samples are placed into the oven at a recommended maximum temperature of 185⁰F.  Sometimes, specimens are conditioned at room temperature of 73⁰F and evaluated before placement into the oven for exposure to heat. After five days, the sets are removed from the oven(s) and all specimens are visually inspected for crazing and cracking in comparison to an unstressed sample using microscopic mapping. Figure 2-Right illustrates uncut polycarbonate being microscopically photographed to serve as a benchmark against stressed specimens.

5. Test Specimens (Ref: EIA-564)

5.1 Test specimens are transparent injection molded polycarbonate IZOD bars per ASTM D256. Clean handling techniques should be observed in the preparation and utilization of the polycarbonate specimens.

6.4 Temperature (Ref: EIA 564)

Maintain one set of exposed and strained polycarbonate bars at each temperature being evaluated, namely 73⁰F, 120⁰F, 158°F and 185°F +/-2°F for five days. Reapply agents that volatilize in order to maintain continued chemical exposure.

After five days, remove the bars from the jigs, wipe clean and inspect visually for crazes and cracks. Some organizations require testing at the maximum 185°F temperature only for 5 days using the strain jigs 1000, 1700, 2000, 2500 and 3400 psi. This serves as a “worst case” scenario at the 185⁰F temperature level.

The test, polycarbonate bars, which have been bent at various stress levels and exposed to the  supplier’s antistatic type agent or static packaging materials are then subjected to various temperatures for 5 days. Later, said specimens are examined for cracks or imperfections.

                 Table 11                      Highest Compatible Stress Level

(1EOS/ESD Symposium in 1989 by Dr. Marv Havens of Cryovac2 )

According to Dr. Marv Havens, “A general rule for polycarbonate compatibility is that there be no serious crazing up to the 2000 psi stress level at 158⁰F.”The data in Table 1 gives the polycarbonate compatibility date for the three versions of Type II film from Marv Haven, Ph.D.   

                Table 2                           EIA 564 Full Testing Series