The production process of white latex adhesive is simple. The process flow is as follows: Add a specified amount of water and polyvinyl alcohol (PVA) into a dissolving tank, then stir to allow the PVA to swell, heat to dissolve, obtaining a PVA solution of the specified concentration. The PVA solution is passed through a filter and then pushed into a polymerization reactor using compressed air. Start the stirrer of the polymerization reactor, heat to a certain temperature, add plasticizer and defoamer. Continuously add vinyl acetate (VAc) monomer and initiator into the polymerization reactor at the specified temperature, controlling the reaction temperature until feeding and reaction are complete. After sampling passes inspection, the product is pushed into a finished product tank through a filter using compressed air, cooled to below 50°C, and then filtered through a strainer to remove solid particle impurities before packaging.

During the production process of white latex adhesive, a large amount of milky white wastewater is generated from filters, reactor washing, etc. The composition of the wastewater is relatively complex, including polyvinyl alcohol (PVA), polyvinyl acetate, plasticizer, defoamer, dispersant, antifreeze, starch, talc powder, unreacted vinyl acetate monomer (VAc), etc. The main components of the wastewater are COD and SS, with an organic content of about 5000 mg/L. The amount of latex wastewater generated from about 16,000 tons of white latex adhesive is about 7,000 tons.

The treatment method for white latex adhesive production wastewater has been to use natural sedimentation followed by discharge for many years. The natural sedimentation method has a long sedimentation time for treating latex wastewater, the sedimentation tanks occupy a large area, and the sedimentation effect is poor. It can only treat large particle colloids. Fine particle colloids remain suspended in the water and do not settle. The natural sedimentation method simply cannot solve the problem of separating colloidal substances from the water in the wastewater. After natural sedimentation, the COD of the discharged wastewater is still above 3000 mg/L, and the SS is around 500 mg/L, far exceeding the comprehensive discharge standard (GB8978-1996).

The above are the production process and wastewater treatment method for white latex adhesive. I hope this is helpful to everyone.