Mangium wood (Acacia mangium) is a fast growing species, which is commonly used as potential raw materials for pulp and paper industries. In Indonesia, pulp and paper industries use kraft pulping or sulfate in the manufacture of mangium pulp. In kraft pulping, mangium woods are cooked in the digester containing solution of caustic soda (NaOH). Its production actually causes a lot of environmental pollution due to liquid waste, black liquor is carelessly discarded.

Black liquor contains organic components such as lignin, resin, tannin and inorganic components form various types of salt [1]. The main components of black liquor are water, inorganic compounds derived from the residual liquid of chemical cooking of wood chips, the reaction products during ripening process and organic compounds derived from wood chips [2].

The percentage of lignin in black liquor was 46% of dry solids. Lignin is the largest component contained in the remaining solution from black liquor. It can be used as an adhesive, rubber fillers and lignosulfonate. Lignin is a thermoplastic polymer, that will able to soften at higher temperature and will harden again when it is cold [3]. Lignin can be partial substitution of synthetic resin in resorcinol formaldehyde adhesive. The benefits of resorcinol formaldehyde are less odor than phenol formaldehyde resistant to weather, climate, high temperatures and deterioration and harden faster at low temperatures [4].

The aim of this research was to isolate lignin from kraft pulping black liquor of mangium wood as lignin resorcinol formaldehyde (LRF) bioadhesive. The information about properties lignin, isolation techniques and their formulation into lignin resorcinol formaldehyde adhesive will be very useful for industrial adhesives and pulp as well as composite products in producing environmentally friendly products.