SYNTHESIS AND PROPERTIES OF ROSIN-POLYETHYLENE GLYCOL DERIVATIVES FOR PRODUCTION OF SOLDERING FLUXES

Abstract

This research aims to synthesize rosin-polyethylene glycol derivatives from rosin and polyethylene glycol (PEG) for the production of solid soldering fluxes. The rosin-PEG derivatives would be water-soluble and the resulting solid soldering fluxes would have reasonable wetting ability when combined with a low halide content activator. The reaction conditions (including catalyst type, catalyst concentration, reaction temperature, and PEG type) were optimized for the synthesis of rosin-PEG derivatives. The chemical and physical properties of rosin-PEG derivatives were characterized by Fourier transform infrared (FT-IR) spectroscopy, carbon-13 nuclear magnetic resonance (13C-NMR) spectrometry, differential scanning calorimetry (DSC), and gel permeation chromatography (GPC). The production and characteristics of water-soluble rosin fluxes (WSRFs) were studied according to the standards of the Japanese Industrial Standards (JIS) Committees. It found that rosin-PEG derivatives were successfully synthesized from rosin and PEG using 2% ZnO as a catalyst, with a 2:1 molar ratio of rosin:PEG at 250 °C over 9 hours. The resulting rosin-PEG derivatives were completely soluble in water. Since the rosin-PEG3000 derivative had the highest melting point (55.2 °C), it was chosen for the preparation of the WSRFs. Activators such as succinic acid, glutaric acid, ethylamine hydrochloride, and diethylamine hydrobromide were selected for use in the production of the fluxes. It was found that WSRF 09 and WSRF 04 gave the best performance with the lead-free Sn-0.7Cu solder alloy in terms of good solderability, low halide content (less than 1500 ppm), high insulation resistance, and low corrosion. WSRFs were stable flux content and extrude-able in lead free solder wire product.