Page 151 - Engineering Plastics Handbook

124 Engineering Plastics

TABLE 6.12 Rubber-Toughened Transparent Resins
Process Refractive index Rubber
Transparent ABS Emulsion, bulk 1.51–1.52 Butadiene
Transparent HIPS Bulk, bulk suspension 1.53–1.56 Styrene-butadiene
Transparent MBS Emulsion, bulk 1.53–1.56 Styrene-butadiene

rubber is higher than that of polybutadiene rubber. Therefore, the
transparent HIPS or transparent MBS uses much more styrene, having
a high refractive index in comparison to the transparent ABS. Further,
a difference in the T values of the rubbers creates a difference in impact
g
resistance at low temperature. For the transparent ABS using polybu-
tadiene rubber, the impact resistance at low temperature (measured
at −30°C) is excellent, about 3 to 5 kg⋅cm/cm.
The transparent resin used commercially includes poly(methyl
methacrylate) resin, polystyrene resin, SAN resin, polycarbonate resin, etc.
Since these resins have both merits and demerits, their use is limited.
Although polystyrene and SAN have very low impact strength, they are
often used as the inexpensive transparent resin that does not demand cer-
tain impact strength, such as for toys, stationery, etc., due to their low price.
Poly(methyl methacrylate) resin has very low impact strength, as does
polystyrene resin or SAN, but can be used as the optical material for
lenses, glass, CDs, etc., due to its excellent optical properties. Although
polycarbonate has excellent transparency and excellent optical proper-
ties, and can be used for any purpose in view of these properties, its prac-
tical use is limited due to its high cost and poor processability.
The transparent ABS has the properties to the intermediate extent
between said resins in mechanical, optical, and processability; therefore,
it has been used for substantially various purposes. Specifically, it has been
used for various fields including housings for electric home appliances
such as washing machines and cleaners; OA supplies such as copiers, fac-
similes, etc.; stationery such as ball pens; toy and medical appliances; and
the like. Further, the use of transparent ABS has been expanded to the
market of existing transparent resin. The toy market, which has used
inexpensive SAN or polystyrene resin, has been converted to the trans-
parent ABS or other materials as the uses of SAN and polystyrene are lim-
ited due to regulation under the consumer’s protection law, such as the
product liability (PL) law. The conversion of the materials to the trans-
parent ABS can be shown similarly in the field of polyvinyl chloride (PVC)
materials. As the use of transparent PVC resin, which has been employed
for semiconductor carriers, etc., has been limited due to the environmen-
tal regulation, the conversion of this PVC resin to other materials has
been researched. Transparent ABS, which has excellent processability
and maintains the required impact resistance, has been regarded as the