Page 157 - Engineering Plastics Handbook

130 Engineering Plastics

In general, although EPDM rubber is more expensive than polybutadi-
ene rubber, the amount of EPDM rubber used in AES resin is as low as
about 60% of the content of polybutadiene used in ABS resin, and there-
fore, the price of AES resin as a whole may be somewhat competitive. In
addition, since the moldability of AES resin is somewhat better than that
of ABS resin, AES resin can be regarded as having high possibility of use
if the environmental problem as mentioned above can be solved.

ACS resin
Since ACS resin contains chlorine, it has excellent properties including
flame-retardant and antistatic properties as well as weatherability. It
has the pale yellow, translucent or white opaque, glossy appearance, and
the properties of the resin are substantially similar to those of ABS
resin, with the impact strength being somewhat high. Since the weather-
ability of ACS resin is excellent, as the falling weight impact mainte-
nance of about 60% after 2 years of outdoor exposure and the elongation
maintenance of about 50% even after 1000 h illustrate, this resin can
be used for 6 to 7 years or more if some stabilizer is added.
Particularly, it has been shown that the flame-retardant property of
ACS resin is sufficiently good for use in the hot-wire ignition and high-
voltage arc ignition test. In addition, the fact that general plastic resin
has excellent electric insulating properties and hygroscopic resistance
generally creates the disadvantage that the resin is easy to charge. To
the contrary, ACS resin has a great advantage in that it is difficult to
charge and there is substantially no surface contamination with dust.
The processing of ACS resin uses the same molding conditions as for ABS
resin, HIPS, etc. However, since ACS resin contains chlorine, and it is
easy to cause thermal decomposition at high temperature, careful atten-
tion must be paid. Therefore, in the injection-molding process, the cylin-
der temperature is set not to exceed 220 to 230°C, and long-term retention
in it must be avoided. In addition, in the extrusion-molding process there
is a necessity for strictly establishing the die temperature at 190 to 220°C.
Secondary processing such as adhesion, hot stamping, and painting can
be practiced in the same manner as for ABS resin. In conclusion, the effect
of ACS resin can be maximized when this resin is used for the product that
simultaneously demands both flame resistance and weatherability.

LG ASA
ASA resin exhibits somewhat low impact strength and significantly
deteriorated staining properties compared to ABS resin. Therefore, ASA
resin has limited use. However, the product has far superior weather-
ability while maintaining the advantages of ABS resins, as they are
recently developed by multilayer structure technology.