Study On Room Temperature Curing Polyurethane Primer Sealer For High-speed Rail Concrete Bridge

Concrete is one of materials which has been widely used in the high-speed railway and bridges, The lacking of substrate wetting, penetration, bonding,interfacial adhesion between with the ordinary paint and concrete is a common problem in engineering applications. According to the characteristics of concrete, the paper designed and synthesized a high-performance two-component polyurethane sealer of room temperature curing which has been used in the high-speed rail and bridge, the concrete sealing primer has good penetration resistance, fast drying, recoat time is short, good adhesion between layers, which has excellent adhesion with concrete and polyurea.According to the particular requirements for concrete sealer, the required hydroxyl polyster resin molecular weight was 4000～8000, functionality of hydroxyl was 3, and the molecular structure with oil group, glycerol as the poly hydroxyl monomer, phthalic anhydride, maleic anhydride, carboxyl monomer acid as the soybean oil, diethylene glycol and benzoic acid acid as the the monomer of molecular weight regulating to synthesis the polyhydroxy resin of the concrete Sealer. The experiments show that, the best method of synthesising of the polyhydroxy resin was the solution polymerization, and the best catalyst was the catalyst A, the optimal ratio of materials for polyol’s mole ratio and polybasic acid’s mole ratio is 1.25:1, phthalic anhydride, maleic anhydride, bean oleic acid is 1:1:1, synthesis process stability and repeatability were relatively good.According to the particular requirements for concrete sealer, we choosed the MDI as a multi-isocyanate monomer, three kinds of polyether EP330N, GE220, GE210 as the connection monomer to synthesis polyurethane prepolymer. The experiments showed using EP330N hydroxyl polyethers to synthesize polyurethane was pre polymer viscosity; using GE220 hydroxyl polyethers to synthesize was pre polymers,[NCO] value was maximum, moderate viscosity; using GE210 hydroxyl polyethers to synthesize polymers was the least viscosity, [NCO] value is minimum. It proved in this paper, the studied concrete primer was the ideal of concrete protective coating, conforming to the needs of the design.This paper studied the type of isocyanate and curing parameters, in the investigation of the stretch mechanics of coating, impact resistance, flexibility, adhesion and sealing performance, it was found that under the same curing parameters and hydroxyl component, different isocyanate beforehand tensile mechanical properties of the polymer coating, impact resistance and flexibility performance mainly introduced by the crosslinking and joint were decided by hard segment content; Under the condition of the same isocyanate pre polymers, with the increasing of curing parameters, the impact flexibility of coating is slightly decreased; Adhesion and seal performance test results showed that the design of the two-component polyurethane coating adhesion and seal performance were very good, the best prescription of concrete sealer, a series of concrete primer test results prove that the research of this paper was the ideal of concrete sealer, meeting the needs of the design...