▎ 摘　　要

NOVELTY - Large pipe diameter inner covered composite hydrophobic coating comprises 10-30 wt.% polytetrafluoroethylene, 20-40 wt.% aqueous epoxy resin, 1-10 wt.% composite inorganic nano-particles, 0.5-2 wt.% auxiliary agent, 2-10 wt.% additive, and water (remaining amount). The auxiliary agent is silane coupling agent or heptafluorodecyltrimethoxysilane. The additive includes dispersant, defoamer, thixotropic agent, and pigment. The composite hydrophobic coating is prepared by e.g. (i) adding polytetrafluoroethylene, aqueous epoxy resin, composite inorganic nanoparticles, auxiliary agent, additive, and moisturizing in batches, and then vigorously stirring or ultrasonic vibration to obtain modified multi-dimensional composite hydrophobic coating, adding the composite inorganic particles and solid additives in a dispersed form, sieving the composite inorganic particles by a sieve or added in the form of spraying from a nozzle with compressed gas as a dispersant. USE - Used as large pipe diameter inner covered composite hydrophobic coating. ADVANTAGE - The coating: has simple preparation method, low curing temperature; and is suitable for the construction of large pipe fittings and large-area parts. DETAILED DESCRIPTION - Large pipe diameter inner covered composite hydrophobic coating comprises 10-30 wt.% polytetrafluoroethylene, 20-40 wt.% aqueous epoxy resin, 1-10 wt.% composite inorganic nano-particles, 0.5-2 wt.% auxiliary agent, 2-10 wt.% additive, and water (remaining amount). The auxiliary agent is silane coupling agent or heptafluorodecyltrimethoxysilane. The additive includes dispersant, defoamer, thixotropic agent, and pigment. The composite hydrophobic coating is prepared by (i) adding polytetrafluoroethylene, aqueous epoxy resin, composite inorganic nanoparticles, auxiliary agent, additive, and moisturizing in batches, and then vigorously stirring or ultrasonic vibration to obtain modified multi-dimensional composite hydrophobic coating, adding the composite inorganic particles and solid additives in a dispersed form, sieving the composite inorganic particles by a sieve or added in the form of spraying from a nozzle with compressed gas as a dispersant, (ii) using modified multi-dimensional composite hydrophobic coating, allowing to stand for no less than 10 hours, and then filtering the coating with gauze or sieve, (iii) before using the multi-dimensional composite hydrophobic coating, insulating at 25-50 degrees C for 0.2-1.5 hours, then brushing, rolling, or spraying on the base material, and(iv) placing the multi-dimensional composite hydrophobic coating at 60-150 degrees C, insulating for 10-60 minutes, internally covering large pipe diameter with composite hydrophobic coating subsequent heat treatment device including thermal insulation coils, support, pipe end seals, and wind baffles, where the composition of electric heating fan and temperature sensor includes maximum heating temperature of the device is 200 degrees C.