Page 284 - Engineering Plastics Handbook

246 Engineering Plastics

4. High DTUL
5. High dimensional stability [low coefficient of thermal expansion (CTE)]
6. Low permeability (low oxygen and water vapor permeability)
7. Flame retardancy
8. Damping properties due to the skin-core structure
9. Chemical resistance

These superior properties of LCP compared with other engineering plas-
tics are shown in Fig.11.4.
Typical grades of GF filled LCPs by various manufacturers are shown
in Table 11.5.

®
SIVERAS GF filled regular grade
®
SIVERAS has an excellent heat resistance that is appropriate for SMT
applications. Here we present several important properties superior to
the typical GF filled LCP materials for SMT applications:
®
1. Moldability (flowability). SIVERAS shows the highest flowability among
all the commercial LCPs, which is reflecting its excellent homogeneity.
2. Flash properties. In general, LCP materials generate low flash during
injection molding compared with other engineering thermoplastics.

Soldering heat
−5
Flexural modulus (GPa) resistance ( ° C) Flowability (mm) CTE [×10 cm/(cm ° C)]
30 300 0.020 in 5
0.020 in 120
25
4
20 250
80 3
15
2
10 200 40
5 1
0 150 0 0
PBT N66 PPS LCP PBT N66 PPS LCP PBT N66 PPS LCP PBT N66 PPS LCP
Water vapor
2
Flash length (µm) Damping (times) permeability [g/(m · day)]
60 12
60
300
40 8
40
200
20
20 4
100
0 0 0 0
PBT N66 PPS LCP PBT N66 PPS LCP PBT N66 PPS LCP
Figure 11.4 Typical properties of LCP compared with other engineering plastics.