Page 146 - Engineering Plastics Handbook

Acrylonitrile-Butadiene-Styrene (ABS) Resin 119

TABLE 6.9 Condition of Sheet
Extrusion Process
Items Conditions

Extruder barrel temperature 200–230°C
Die temperature 210–240°C
Resin melt temperature 220–250°C
Roll temperature 70–90°C

styrene-butadiene rubber and the shell component is comprised of a
random copolymer of styrene, acrylonitrile, and methyl methacrylate.
This resin is a macromolecular substance having all the properties of four
kinds of components constituting the resin, i.e., processability derived
from styrene, chemical resistance and excellent physical properties derived
from acrylonitrile, impact resistance derived from butadiene, and optical
property derived from methyl methacrylate. It is structurally similar to
ABS, but uses methyl methacrylate, in addition to styrene and acryloni-
trile used for ABS, as the shell component to be consistent with the refrac-
tive index of rubber used as the core, thereby providing a transparency.
The refractive index of the respective component is 1.516 to 1.518 for
polybutadiene, about 1.49 for poly(methyl methacrylate), 1.592 for poly-
styrene, and about 1.52 for polyacrylonitrile. The refractive index (RI)
of the grafting copolymer can be calculated according to
RI = Wt ⋅ RI + Wt ⋅ RI + Wt ⋅ RI M
A
A
M
S
S
Where Wt = weight percent of acrylonitrile
A
RI = refractive index (1.52) of polyacrylonitrile
A
Wt = weight percent of styrene
S
RI = refractive index (1.592) of polystyrene
S
Wt = weight percent of methyl methacrylate
M
RI = refractive index (1.49) of poly(methyl methacrylate)
M
The composition of each respective component can be calculated so that
the refractive index of the grafting copolymer as calculated from the above
Preheating Blow process Plug assist process Cooling & extraction

Pressure
Vacuum Vacuum
Figure 6.9 Vacuum forming process.