Preparation And Properties Research Of High-strength And Low-temperature Curing Reinforcing Sheet

It is an important task for all countries to slow down global warming and reduce carbon dioxide emissions.In this context,the automobile industry has two development directions: one is to change gasoline and diesel to electric to reduce oil consumption;the other is to improve the energy conversion efficiency of internal combustion engine and reduce carbon dioxide emissions.Whether in electric vehicles or diesel locomotives,vehicle lightweight is an important means to improve power,reduce fuel consumption and reduce exhaust pollution.In the lightweight of automobile components,the stencil thickness of the automobile doors and the side panels is constantly decreasing.In order to ensure the mechanical strength of the automobile body,on the one hand,high-strength steel plates are used to replace the original ordinary steel plates;on the other hand,reinforcing sheet is used to strengthen the weak parts.At present,there are reinforcing sheets for welding and coating on the market,but the thickness of welding reinforcing sheet is generally 1.5 mm,which cannot meet the high reinforcement requirements of automobile factories after the thickness is reduced.At the same time,in order to meet the requirements of automobile factory for energy conservation and emission reduction and furnace temperature reduction,low-temperature curing of coating reinforcing sheet is also an urgent problem to be solved.In this paper,high-strength reinforcing sheet is used in automobile welding workshop and low-temperature curing(135? × 20 min)reinforcing sheet is used in coating workshop for preparation and research.It was found that when modified bisphenol A epoxy resin ERS172 was combined with ordinary epoxy resin YD128,the composite ratio was 2:1 and the total amount of epoxy resin accounted for 30wt%,the comprehensive performance of the high-strength reinforced sheet was the best.When the dosage of foaming agent OBSH is 0.3 wt%,the reinforcement ratio of 0.8mm high-strength reinforcing sheet is equivalent to that of 1.5 mm ordinary welding reinforcing sheet,and the former can be used to replace the latter to reduce the weight of the sheet.The reinforcement ratio of coating reinforcing sheet added 0.6 wt% UR700 baked at 135? for 20 minutes is equivalent to that of common coating reinforcing sheet baked at 150? for 20 minutes twice.The reinforcement ratio of 2.5 mm reaches2.2 times,and the maximum force reinforcement ratio reaches 4.3 times.The more the amount of UR700,the smaller the penetration and initial adhesion of thereinforced film after 168 h at 40?.When the dosage of UR700 is 0.6 wt%,after the sheet being stored at 40? for 168 h,the penetration decreases from 48 to 45(0.1mm),and the initial adhesion decreases from 11 N/25 mm to 9 N/25 mm.The performance changes within the standard range,and the dosage of UR700 is selected as 0.6 wt%.