Dimensional Stability of SUMIKAEXCEL PES

Coefficient of Linear Expansion

SUMIKAEXCEL PES possesses the special properties of having both a low coefficient of linear expansion and a low temperature dependence. Figure 1 depicts the temperature dependence of the coefficient of linear expansion. The coefficient of linear expansion of crystalline PPS (40% GF) increases as the temperature rises. However, the coefficient of linear expansion of amorphous SUMIKAEXCEL PES is not temperature-dependent and maintains a constant value up until a temperature of 200 deg C. Furthermore, 4101GL30, a glass fiber reinforced grade, possesses a coefficient of linear expansion as low as that of aluminum, which is 2.3x10-5 /deg C. For this reason, 4101GL30 is considered to be a suitable material for usage in precision molding applications.

Figure 1 Temperature dependability of a coefficient of linear expansion

Figure 1 Temperature dependability of a coefficient of linear expansion

Mold Shrinkage

Non-reinforced grades of SUMIKAEXCEL PES have low mold shrinkage (0.6%) and no anisotropy. However, glass fiber reinforced grades possess anisotropic shrinkage, at 0.2% for MD and 0.4% for TD due to the orientation of GF.

Figure 2 Mold Shrinkage Comparison

Figure 2 Mold Shrinkage Comparison

Dimensional Changes Due to Water Absorption

SUMIKAEXCEL PES is susceptible to water absorption. From our experiences, however, it is at most 1.1% remain in wait change and 0.15% remain in dimensional change if the test piece is left in the air for long time (until saturated condition).

Figure 3 Water Absorption Dependence of Dimensional Changes

Figure 3 Water Absorption Dependence of Dimensional Changes
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