Composite polyester hot-melt adhesive and preparation method thereof and preparation method of anti-scouring geotextile

A preparation method of a composite polyester hot-melt adhesive, comprising the following steps:

• (1) performing an esterification reaction on a dibasic acid and a dihydric alcohol under a protection of nitrogen and an action of a titanium/cobalt composite catalyst;
• wherein the titanium/cobalt composite catalyst is a cobalt catalyst and a titanium catalyst, the cobalt catalyst is cobalt acetate, and the titanium catalyst is one selected from the group consisting of tetrabutyl titanate, tetraisopropyl titanate and tetramethyl titanate;
• an addition amount of the titanium/cobalt composite catalyst is 0.01%-0.03% of a total mass of the dibasic acid, the titanium catalyst accounts for 65-75 wt % of the titanium/cobalt composite catalyst, and the cobalt catalyst accounts for 25-35 wt % of the titanium/cobalt composite catalyst;
• the temperature of the esterification reaction is 180° C.-200° C.;
• terminating the esterification reaction when distillate water of the esterification reaction is 95%-98% of a theoretical water yield of the esterification reaction to obtain an esterification product;
• and
• wherein, the mass ratio of the dibasic acid and the dihydric alcohol is 1:(1.2-1.5);
• the dibasic acid is a mixture of terephthalic acid, isophthalic acid and 2-phenyl glutaric acid with a molar ratio of 1:(0.10-0.30):(0.10-0.30);
• the dihydric alcohol is a mixture of diethylene hexanediol, diethylene glycol and 1,4-butanediol with a molar ratio of (1.0-1.2):(0.5-0.7):(0.2-0.4);
• (2) after holding for 30 min-50 min, adding a stabilizer to the esterification product to obtain a first mixture, and continuously raising the temperature of the first mixture to 230° C.-240° C.;
• reducing the pressure to 80 Pa-100 Pa to conduct a polycondensation reaction on the first mixture for 1.5 h-3 h to obtain a polyester hot-melt adhesive;
• (3) adding polymethyl methacrylate (PMMA) microspheres and gluconolactone into the polyester hot-melt adhesive under normal pressure and the protection of nitrogen to obtain a second mixture, and mixing and stirring the second mixture for 1 h-1.5 h at 230° C.-240° C. to obtain the composite polyester hot-melt adhesive, wherein an amount of the gluconolactone is 0.1 wt %-0.3 wt % of the polyester hot-melt adhesive.