|
Wind power is encouraged by the state and much needed energy saving projects. Wind turbine blades open work load to withstand strong winds, sand erosion, ultraviolet radiation, atmospheric oxidation and corrosion, salt corrosion, material costs and other aspects have higher requirements. Currently megawatt wind turbine blades have been made of carbon fiber reinforced epoxy composites, the required low viscosity epoxy resin required for fiber penetration, good impact resistance, good toughness. Universal type epoxy resin viscosity, impact resistance and poor weather, easy to powder paint outdoors due to loss of light and fullness, not suitable for outdoor use coatings and adhesives. Development of new wind turbine blade epoxy resin has very important significance. New bisphenol F epoxy resin with a low viscosity, solvent resistance, high impact resistance, and the fibers impregnated with FRP composite performance, using low cost and to be optimistic for the manufacture of wind turbine blades based molding material. The main raw material bisphenol F in a foreign country has produced, but the presence of high phenolic ratio, the best performance of para isomer content is low, low yield, after dealing with complex issues such as the product, and the use of large multiples of phenol circulation evaporator Apply again in the reaction under heating, resulting in higher production costs. The high price of imported bisphenol F, bisphenol F epoxy resin resulting in domestic small-scale production. Firstly, with phenol and formaldehyde in the presence of phosphoric acid catalyst and methanol solvent under preparation for electrophilic substitution reaction of bisphenol F, studied the ratio of raw materials, the amount of phosphoric acid catalyst, reaction temperature and time on the yield and the right-isomer content of the body, to obtain the optimum process parameters: phenol / formaldehyde (mo1) = 5:1, methanol / formaldehyde = 1:1 phenol / phosphoric acid = 3:1, water / acid = 2.5 to 3.0 / 1, the reaction temperature 45 ℃, reaction time 5h, the reaction conditions, bisphenol F, the yield was 92.2% (as formaldehyde, formaldehyde per mole of bisphenol F can be obtained by mole), and the resulting product of bisphenol F 4, 4'-isomer content of 73.2%. Bisphenol F with epichlorohydrin and then tetramethylammonium chloride in the presence of a catalyst for the etherification reaction, and then addition of solid sodium hydroxide epoxidation dechlorination reaction, and then purified to obtain a bisphenol F epoxy resin. Ratio of the raw materials, reaction time and temperature on the chlorine content and the epoxy value of, and the suitable process conditions: epichlorohydrin / bisphenol F (mol) = 10:1, dichloropropanol / Ring epichlorohydrin = 0.2, the amount of tetramethylammonium chloride was 2% (mol / BPF), etherification temperature was 80 ℃, time was 5h, epoxidation catalyst is powdered sodium hydroxide, an excess of 2%, closed-loop temperature to 70 ℃, time is 1.5 ~ 2.0h. In this process conditions to obtain a bisphenol F type epoxy resin as a pale yellow, transparent, low-temperature fluidity, the yield was 91%, an epoxy value reached 0.57, the organic chlorine was 2.1 × 10-4, the inorganic chlorine 1.3 × 10-4. The Fourier transform infrared spectroscopy and NMR analysis, the initial recognition of the synthesized product is bisphenol F epoxy resin.
|