Study on Anti-tracking Properties of Unsaturated Polyester Resin SMC
A method of thickening hydroxyl-terminated unsaturated polyester with polyurethane (PU) that comes from the reaction between diisocyanate compounds and polyglycol is introduced, and the effect of PU prepolymer on the anti-arc properties of the sheet molding compounds (SMC) is studied according to the standard of ASTM, the electric strength is tested in the transformer oil under 423K, 453K, 473K, 523K respectively. The anti-tracking properties of UP-SMC were developed when Al(OH)3  and diisocyanate compounds were filled in UP-SMC. The microstructure of UP-SMC struck by electric arc was observed by means of SEM (Scanning Electron Microscopy). The results show that UP-SMC samples with no anti-tracking modification have some part of ablation and charring while the modified sample are with the low electric rot. The arc breakdown time would increase with the usage of PU. The SMC thickened by PU shows good aging resistance as well as anti-arc properties, it will be widely used on electrical parts and arc-deflecting cover of AC switch etc
Flame retarded polymeric material
The invention relates to a polymer material comprising a halogen-free flame-proofing agent incorporated into the polymer matrix, the flame-proofing agent comprising at least ammonium polyphosphate(s) and/or derivatives thereof and an oligomer or polymer 1,3,5-triazine derivative or mixtures of a plurality thereof and at least one compound selected from phosphates, pyrophosphates, polyphosphates, organic and inorganic phosphonates, organic and inorganic phosphinates, stannates, molybdates or borates of the elements of the main groups II, III, IV or of the sub-group elements Fe, Zn, Ti, Mn, Zr, Mo, pre-condensed melamine derivatives, melamine salts and addition compounds, ethylene diamine phosphate, piperazine phosphate, piperazine polyphosphate, 1,3,5-trihydroxyethyl isocyanurate, 1,3,5-triglycidyl isocyanurate and triallyl isocyanurate. The weight ratio of constituents A to constituents B is 10:1 to 1 :1, constituents A and B together amounting to between 60 and 99 wt. % and constituents C and D to between 1 and 40 wt. % of the total weight of constituents A, B, C and D. The polymer material is a thermoplastic elastomer (TPE).
On the thickening mechanism of unsaturated polyesters by alkaline earth oxides and hydroxides
The mechanism that describes the thickening process of unsaturated polyester resins with inorganic oxides and hydroxides is presented. This mechanism includes the formation of water, the formation of the ion cluster, the network expansion and the equilibrium, where the viscosity reaches a constant value.