Preparation method of modified bone glue leather tanning agent

The invention provides a preparation method of a modified bone glue leather tanning agent. The preparation method comprises the steps that bone glue is adopted as a raw material and is firstly degraded under the alkali condition, then the pH value is adjusted to an acid value and a neutral value, then aluminum salt is added to carry out coordination modification on the degraded bone glue, and the modified bone glue leather tanning agent is obtained. The bone glue is adopted as the raw material and is quite wide in source, low in cost and excellent in performance. The bone glue has the beneficial effects of being high in bonding strength, low in price, biodegradable, free of pollution and the like, amidogen and carboxyl exist in bone glue molecules and can form hydrogen keys with active groups in collagen, so that the bone glue is properly degraded and coordinates with aluminum ions, and the bone glue can serve as the good tanning agent. Degrading modification research is carried out on the bone glue, and the modified bone glue leather tanning agent which is excellent in performance and environment-friendly and has certain washing resistance is successfully prepared and can replace existing chrome tanning agents high in toxicity and serious in pollution. The method is simple in preparation technology, low in production cost and suitable for industrial large-scale production.