Joint adhesive for adhering joint of door/window profile and preparation method of joint adhesive

The invention provides a joint adhesive for adhering the joint of a door/window profile and a preparation method of the joint adhesive. The joint adhesive is prepared from the following raw materials in parts by weight: 6-8 parts of sodium based bentonite, 1-3 parts of borax, 5-7 parts of sodium silicate, 3-5 parts of polyving alcohol, 2.5-5 parts of milled wood lignin, 4-6 parts of oxalic acid and 800-900 parts of water. The preparation method comprises the following steps: preparing the raw materials according to the formula; adding water into a reaction kettle, and heating to be 70 DEG C; adding polyving alcohol in a slow flowing mode, stirring, and heating to dissolve the materials until no granules are retained; cooling to 40-45 DEG C, slowly adding sodium based bentonite, borax, sodium silicate, milled wood lignin and oxalic acid into the reaction kettle when continuously stirring, sufficiently stirring and mixing, further heating to be 65-70 DEG C, after polymerization reaction is completed, heating to be 80-90 DEG C, and stopping heating; after 10-20 minutes after the polymerization reaction, cooling to be less than 50 DEG C; step 6, sampling, testing the viscosity, the pH value and the solid content, and after the indexes are all qualified, cooling and packaging. The joint adhesive is high in adhesion property, free of formaldehyde, free of toxicity, free of environment pollution, and low in cost.