Study On Preparation And Properties Of Rosin-Based High-Efficiency Flux

As one of the commodity forest chemical products in China,rosin,an indispensable raw material in the light industry,chemical industry,electrical appliances,national defense and other fields.Since natural rosin has shortcomings such as easy oxidation,low softening point,and high brittleness.My work will modify the composition of active groups such as conjugated double bonds and carboxyl groups in its structure through modification,in an attempt to improve stability and comprehensive performance to a certain extent.Rosin and its modified rosin products have excellent film-forming properties,electrical insulation,thermal conductivity,high temperature fluidity,and moisture resistance,as well as strong reactivity with metal oxides,which can remove the metal surface during the soldering.Oxide,the formation of electrical insulation and hydrophobic protective film on the surface of the solder joints,the promotion of flow and heat transfer,and the adjustment of viscosity,etc.,are the ideal flux components for highly adaptable lead-free solders currently being promoted to modify.Rosin-based fluxes with modified rosin as the component have been applied more actively in the field of electronic soldering in recent years.In line with improving the utilization value of rosin and expanding its application range,this paper takes natural rosin as the raw material to carry out the development and performance research of rosin-based high-efficiency flux.The main research contents include synthesis of high acid value and high softening point rich Horse rosin/Maleic rosin,develop fumaric rosin/maleic rosin-based liquid flux,and comprehensive test of flux performance.The main research results of the paper are as follows:1.Fumaric rosin and ma'leic rosin with high acid value and a high softening point was synthesized.The influence of main factors such as the ratio of raw materials,reaction temperature,and reaction time on the performance of the synthesized product was investigated through single factor experiments.Response surface methodology(RSM)was used to optimize the synthetic process conditions,a mathematical model of the main factors affecting the acid value of the synthetic product was established,and the synthetic products were characterized by Infrared Spectroscopy(IR).(1)Rosin and fumaric acid are used as raw materials to synthesize fumaric rosin.The optimized technological conditions were as follows:the mass ratio of raw materials(m fumaric acid:m rosin)=2.9:10,reaction temperature 189.7?,reaction time 2.16 h,The mathematical model of acid value of the synthesized product on main influencing factors is as follows:Yi=271.1+2.46A-19.55B+31.65C+15.78AB+29.11 AC-3.69BC-66.38A2-19.91 B2-20.62C2(Yi—acid value,A—reaction time,B—Reaction temperature,C—raw material mass ratio),the order of influence of various factors on product acid value was as follows:raw material mass ratio>reaction temperature>reaction time,fumaric rosin acid value reaches 296.45 mgKOH/g.(2)Rosin and maleic anhydride as raw materials to synthesize maleic rosin.The optimized process conditions are as follows:the mass ratio of raw materials(m maleic anhydride:m rosin)3:10,reaction temperature 196.5?,reaction time 1.4 h.The mathematical model of the value of the main influencing factors for synthesizing product acid is:Y2=253.34-8.24A-4.2B39.80C+13.67AB-5.61AC+3.86BC-13.75A2-23.92B2-10.94C2(Y2—acid value,A—reaction time,B—Reaction temperature,C—raw material mass ratio),the order of influence of various factors on the acid value of the product is as follows:raw material mass ratio>reaction time>reaction temperature and the acid value of maleic rosin reached 281.48 mgKOH/g.2.A rosin-based flux with multi-solvent and multi-active substance was prepared by using fumaric rosin with high acid value as a film-forming agent.(1)Taking the expansion rate of the flux as the main inspection index,combined with the morphology of the solder joints,based on comprehensive consideration of the nature of the substance itself,the proper role in flux and independent to help flux effect,the type of solvent and active substance have been determined,and the solvent was optimized by the compounding ratio and active material compounding ratio through orthogonal experiments.Then,the multi-solvent,multi-active substance fumaric rosin flux formula was developed.The composition of the compound solvent in the fumaric rosin flux is:V(ethanol):V(isopropanol):V(diethylene glycol butyl ether):V(glycerol)=3:3:3:1,compound The active material composition is:m(succinic acid):m(succinic acid):m(malonic acid)=4:4:2,the formula of fumaric rosin flux:?(fumaric rosin)15%,?(compound active substance)5%,?(OP-10)1%,?(compound solvent)79%.The self-made fumaric rosin flux is applied to the Sn0.7Cu,Sn37Pb,and Sn0.3Ag0.7Cu solder wires.The expansion rate of the solder wire reaches 81.16%,80.21%,and 82.32%,respectively,reaching the GB/T 9491-2002 Liquid Flux for Soldering(Rosin)the quality standard of RA type flux(medium-active rosin-based flux),which has strong adaptability to solder wire;the solder joints produced is relatively complete,continuous,and smooth;there is no delamination and precipitation phenomenon,and the physical stability is good;The content of non-volatile was low(23.55%);no obvious corrosion after welding occurred.(2)The raw materials rosin,fumaric rosin,maleic rosin,and Arakawa rosin were used to formulate flux according to the optimized flux formula.Sn0.7Cu,Sn37Pb,and Sn0.3Ag0.7Cu solder wires are selected to compare the flux performance of these four rosin-based fluxes.The experimental results show that fumaric rosin has the best expansion rate in the three solder wires,and it exhibits good wettability in the Sn0.3Ag0.7Cu solder wire with an expansion rate of 82.32%.The three rosin fluxes have an expansion rate of more than 80%,reaching GB/T 9491-2002 "Liquid Flux for Soldering(Rosin-based)" RA type standard,and the resulting solder joints are very bright and full Good formability.The three kinds of rosin fluxes all have an expansion rate of more than 80%,reaching the standard of RA type rosin flux.The expansion rate of lead-containing solder Sn37Pb is not as good as the other two lead-free solders,which proves that the rosin-based flux has better compatibility with lead-free solders.