Low Viscosity Technology Liquid Silicone Rubber
Bruno Antonio Cuocci
Silicone rubber is very well known for high and low temperature resistance. It is the material of choice for food contact, baby care and medical applications thanks to its chemical inertia.
High Temperature Vulcanizing silicone rubber grades (HTV) are available mainly for extrusion, molding, calendering or coating processing methods.
Injection molding can be performed both with high consistency compounds as well as with Liquid Silicone Rubber (LSR) grades specifically designed for Liquid Injection Molding (LIM). These materials are usually delivered as two component kit (1:1 A+B) that typically show a viscosity around 400 Pa·s.
The key advantages of the Liquid Injection Molding process are short cycle times, a fully automated process as well as a high output rate with no waste. This process requires specific machines and high technology molds equipped with cold runners.
Dow has recently introduced a range of LSR grades whose viscosity is 200 Pa·s or below. This new low viscosity LSR family brings a number of advantages in Liquid Injection Molding process, in particular related to process consistency, parts quality and cost-in-use.