Natural Rubber Latex Adhesives vs Solvent Based Adhesives
John Woon (Senior Latex Consultant): Generally, while latex based adhesives are environmentally friendly, it also offers the following advantages over the solvent based adhesives:
1) Latex has a low viscosity at high solid content. For instance, NR latex concentrate with a total solid content of about 60% has a viscosity of only 150 to 200 mPa.s whereas a rubber solution of about 17% has a viscosity of 60,000 to 100,000 mPa.s.
2) The low viscosity of latex allows it to be easily applied by spraying and roller coating.
3) The high solid content of latex allows for high coating weight (dry) to be achieved with minimal number of coating.
4) For solvent based adhesives the rubber is frequently masticated to breakdown of the rubber molecules before use to ease dissolution in solvents. This results in the weakening of the cohesion strength of the adhesives. Latex based adhesives do not have this problem.
5) Owing to the absence of solvent, latex adhesives do not pose as health and fire hazards. There is no need for expensive procedures and precautionary actions such as the use of flame-proof motors, maximum ventilation, flame-proof lighting and segregation from other production processes.