Chemical Resistance of TORELINA™

TORELINA™ offers excellent resistance to chemical substances such as acids, alkalis, and organic solvents. At 200℃ or below, it will not dissolve in any organic solvent. If, however, it is constantly in contact with concentrated hydrochloric acid, concentrated sulfuric acid, nitric acid, amines, or halogenated hydrocarbons at high temperatures, its properties will be adversely affected.

Ⅰ. Chemical Resistance of TORELINA™

1 Chemical Resistance (General)

The chemical resistances of glass fiber reinforced PPS (A504X90), high-filler PPS (A310MX04), and elastomer improvement PPS (A575W20) are listed in Tables. 8.1 to 8.3. TORELINA™ is excellent in terms of its chemical resistance, and it is particularly resistant to hydrocarbons such as gasoline and oil. It is thus suitable for car engine and motor peripheral parts. On the other hand, it is somewhat less resistant to acids and alkalis at high temperatures. For high-filler PPS, in particular, sufficient consideration must be given if it is in contact with nitric acid for a long period of time, regardless of the temperature.

Table. 8.1 Chemical resistance of glass fiber reinforced PPS (A504X90)

Table. 8.2 Chemical resistance of high-filler PPS (A310MX04)

Table. 8.3 Chemical resistance of elastomer improvement PPS (A575W20)

2 Acid Resistance

If glass fiber reinforced PPS is immersed in dilute sulfuric acid, as used in batteries and so on, it initially tends to exhibit a decrease in strength, but then gradually exhibits a state of equilibrium. It is thought that the deterioration is small, and akin to a plasticizer-like effect due to the absorption of liquid. (Fig. 8.1) If, however, the PPS is immersed in dilute nitric acid, as used for etching and so on, a decreases in strength initially occurs due to the absorption of liquid, in the same way as with dilute sulfuric acid. Then, however, the strength of the PPS continues to be adversely affected over time. Therefore, it is assumed that a steady deterioration is in progress. For this reason, if the PPS is in to be in contact with nitric acid, among others, at high temperatures for an extended period, sufficient consideration of this affect must be taken into account. 　(Fig. 8.2)

• Fig. 8.1 Treatment with 10% sulfuric acid (80℃ treatment)
• Fig. 8.2 Treatment with 10% nitric acid (80℃ treatment)

3 LLC Resistance

If TORELINA™ is immersed in long life coolant (LLC), the main component of which is ethylene glycol, its mechanical properties tend to be slightly adversely affected if the temperature is above the glass transition temperature. (Fig. 8.3) This differs depending on the PPS polymer structure, the reinforcement content, and other factors, but given that it reaches a state of equilibrium in a fixed period, it is thought that these decreases are not due to any deterioration but to the influence of the plasticizer-like effect caused by the absorption of liquid. For A504X90 and A310MX04, in particular, the initial decreases in strength are considerable at temperatures of 150℃ or above, so the tendency is for the LLC to diffuse into the specimen quickly. (Fig. 8.4) An elastomer improvement grade of TORELINA™, A673M, offers excellent LLC resistance, and is capable of retaining its high strength over a wide range of temperatures. It is thus suitable for liquid cooling parts in cars and so on. The LLC resistance evaluation in this technical document is based on 50 vol%, assuming use in cold areas of Japan.

• Fig. 8.3 50% LLC resistance (130℃ treatment)
• Fig. 8.4 50% LLC resistance (150℃ treatment)

Comment) 50% LLC: Toyota genuine super LLC: water = 1:1

4 Oil Resistance

If immersed in automatic transmission fluid (ATF) at temperatures equal to the glass transition temperature or above, TORELINA™ does not exhibit a major change in weight, and only a small decrease in strength. Thus, it offers excellent oil resistance. In particular, the linear polymer type (A604) retains its mechanical properties better than the cross-linked polymer type (A504X90), and offers superior oil resistance. (Fig. 8.5)
If in contact not only with ATF but also with other commercially available, general-purpose oils (such as CVTF and engine oil) for an extended period and at high temperatures, TORELINA™ exhibits only small decreases in strength, and thus is highly resistant to these oils. (Fig. 8.6)

• Fig. 8.5 ATF resistance (150℃ treatment, ISO type A1)
• Fig. 8.6 Oil resistance of A504X90 (150℃ treatment)

5 Fuel Resistance

TORELINA™ offers excellent fuel resistance. For reinforced PPS, there is hardly any degradation in the mechanical properties. (Fig. 8.7) The molecular structure of PPS features aromatic rings that are linked together, so it has a high affinity for the aromatic components of gasoline, light oil, and so on. Therefore, weight changes tend to be slightly greater than with oils. PPS has a particularly high affinity for the toluene found in gasoline alternatives (such as Fuel C), and this strongly influences the weight change. Such weight changes differ not only with the test fuel type and the test temperature but also with the polymer structure, the reinforcement content, and whether the PPS is improved with elastomers. (Fig. 8.8) High-filler grades, which use cross-linked polymer types, such as A310MX04, are suitable for applications subject to dimensional fluctuations due to fuel swelling.

• Fig. 8.7 Fuel resistance (A504X90, ASTM No. 1 dumbbell)
• Fig. 8.8 Fuel resistance (80℃ treatment, Fuel C/15% methanol)

Comment) Fuel C: Isooctane:toluene = 50:50 (vol%)

6 Transmission of Gases

Table. 8.4 Transmission rates of TORELINA™ for gases (23℃)