The invention relates to the technical field of waterproof agents for fabrics, and particularly discloses a
fluoride-free waterproof agent for fabrics and a preparation method of the
fluoride-free waterproof agent. The preparation method specifically comprises the following steps: dehydrating
polyol / ester, adding
isocyanate, heating to 80-90 DEG C, reacting for 2-3 hours, cooling, dropwise adding a chain
extender, reacting for 0.5-1 hour at 45-48 DEG C, adding POSS, stirring for 1-2 hours at 45-48 DEG C, adding an acrylic
monomer A for blocking, cooling, dropwise adding acid, stirring and neutralizing to obtain a
prepolymer; pouring the
prepolymer into water, stirring and emulsifying to obtain a POSS-PU
emulsion; quickly stirring the POSS-PU
emulsion, an acrylic
monomer B, an emulsifier, water, a co-emulsifier, a pH
regulator and the like to obtain a composite
emulsion; homogenizing the composite emulsion until the composite emulsion has obvious
blue light; and adding dodecanethiol and an azo
amidine initiator, reacting at 68-70 DEG C for 3-7 hours, cooling, filtering and taking out to obtain the
fluoride-free waterproof agent.