Short-Term Peak Temperature Loads

An extreme example for short-term peak temperatures is the soldering process. Soldering temperature resistance of circuit boards is defined by several standards with corresponding testing methods. However, they cannot be meaningfully applied to injection molded circuitry (MID Molded Interconnect Device). 

The degrees of crosslinking obtained correlate with the penetration temperatures of the soldering rod. This ensures a residual stiffness that has a positive effect on temperature resistance to the heated soldering tip [720]. 

The short-term thermal resistance to the soldering tip of the PBT materials investigated increased with higher radiation doses [720]. 

Left non-crosslinked clearly deformed Right crosslinked (5 x 33 kGy) little deformation 

In the temperature range from 230 to 280 °C, which is relevant for lead-free soldering, the crystalline regions in thermoplastics will melt. In non-crosslinked plastic films, there are no sufficient bonds left to hold the material together. The crystallites in crosslinked thermoplastics also melt, but the chemical crosslinking bonds hold the macromolecule together in its amorphous zones so that they can keep their shape - even at low stiffness levels. The crosslinked film remains sufficiently strong and stable short-term up to approx. 300 °C [720]. 

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Peak temperature load 676 Short-term behavior... 

Because of the narrow melting range of PA 11, parts can withstand short-term temperature peaks of 100 to 130 °C. For extended temperature loads above 65 °C, the use of stabilized polyamide 11 is recommended. 

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