A latex is a colloidal suspension of very small polymer particles in water and is used to make rubber. Natural latex is tapped from rubber trees (Hevea brasiliensis) as latex in Southeast Asia and other parts of the world, Latex is a colloidal dispersion of solid particles of the polymer polyisoprene in water, Polyisoprene (C5H8)n is the chemical substance that comprises NR, and its content in the emulsion is about 30%. Preferred method to recover rubber from latex involves coagulation – adding an acid such as formic acid (HCOOH). The coagulum, now soft solid slabs, is then squeezed through rolls which drive out most of the water and reduce thickness to about 3 mm (1/8 in). The sheets are then draped over wooden frames and dried in smokehouses for several days, The resulting rubber, now in a form called ribbed smoked sheet, is folded into large bales for shipment to the processor, In some cases, the sheets are dried in hot air rather than smokehouses, and the term air‑dried sheet is used, This is considered a better grade of rubber, that called pale crepe rubber, involves two coagulation steps, followed by warm air drying.