Rock wool board water repellent agent and preparation method thereof

The invention relates to a rock wool board water repellent agent and a preparation method thereof. The raw materials comprise the following components: dodecylbenzene sulfonic acid, alkylphenol ethoxylates, higher alcohols, dibutyltin dilaurate and a dimethyl cyclosiloxane mixture in a mass ratio of (5-10): (5-10): (1-5): (1-3): (70-90), and the content of D4 in the dimethyl cyclosiloxane mixtureis 70-78%. The method comprises the following steps: adding the alkylphenol ethoxylates, the higher alcohols and the dodecylbenzene sulfonic acid into water, heating to 65-80 DEG C, adding the dimethyl cyclosiloxane mixture, reacting, keeping the temperature for 4-6 hours, and carrying out condensation reaction; and adding the dibutyltin dilaurate to carry out crosslinking reaction, keeping the temperature for 2-4 hours, lowering the temperature to below 30 DEG C, and regulating the pH value to 4.5-6.5 by using a sodium hydroxide water solution. According to the invention, the cost is low, andthe product is endowed with better adhesiveness and hydrophobicity.