Study On Flexible Unsaturated Polyester Resin

Flexible unsaturated polyester resin is one of the special kinds of unsaturated polyester resin (UPR). It can be cured at room temperature. After being cured, it has a good flexility and can be made into furniture and floor wood-like products. Besides, it can be mixed with some fillers, such as talcum powder, limestone, light-pearl and so on, and then made into products having different flexility and properties. It can also be mixed with sand to make the road surface of street and bridge, which only contains 7-8wt% flexible unsaturated polyester resin. Another important use of flexible unsaturated polyester resin is that it can be used as a modification resin to improve the toughness of other resins. In this paper, the following aspects of flexible unsaturated polyester resin were studied: the synthesis, applications and relative mechanisms.To enhance the toughness of general unsaturated polyester resins, two kinds of flexible unsaturated polyester resins were synthesized, which were mainly synthesized with adipic acid and poly-ether glycol respectively. The properties of them were also compared. The effects of different contents of adipic acid and poly-ether glycol, degree of cross linking, acid value, cross linker and curing system on the properties of flexible unsaturated polyester resin were studied. It was found that the properties of flexible unsaturated polyester resin synthesized with poly-ether glycol were better than the one with adipic acid, whose tensile strength reached 2.438MPa and elongation at break reached 61.4%. The better combination properties of flexible unsaturated polyester resin could be gotten by adding 33-36wt% styrene (St) into the UPR. The methyl ethyl ketone peroxide (MEKP) had unanimous influence on the curing of flexible unsaturated polyester resin while the cobalt naphthenate did not. Excessive use of cobalt naphthenate wouldn't accelerate the curing speed. In practical applications, the proportion of MEKP and cobalt naphthenate was in the range of 0.8-1wt%, and the ratio of them was offen 1 : 1. The nanometer SiO₂ could...