Preparation method of alkyl ketene dimer papermaking sizing agent and product

The invention provides a preparation method of an alkyl ketene dimer papermaking sizing agent. The preparation method comprises the following steps: mixing a hectorite aqueous dispersion with acetone, ammonia monohydrate and hexadecyl trimethyl siloxane, and carrying out ultrasonic dispersion to obtain a mixed solution I; adding tridecafluorooctyltriethoxysilane into the mixed solution I, and carrying out ultrasonic dispersion to obtain a mixed solution II; drying the mixed solution II to obtain modified hectorite powder; mixing the modified hectorite powder with perfluorohexane, carrying out ultrasonic dispersion, adding molten AKD, conducting mixing and heating, and carrying out ultrasonic emulsification to obtain an AKD-A emulsion; and mixing the AKD-A emulsion with a sodium dodecyl sulfate aqueous solution, and carrying out ultrasonic emulsification to obtain the alkyl ketene dimer papermaking sizing agent. The sizing performance of the AKD emulsion prepared by the method disclosed by the invention is rem