Carl Morrison Monroe

Fabricating With Liquid Silicone Rubber

During the last several years, new systems have been developed for the production of silicone rubber parts. These systems offer major reductions in both capital and labor costs. This paper discusses these developments with an emphasis on material properties and potential benefits to the user. The principal methods used to produce molded parts and supported extrusions from liquid silicone rubber are described. Advantages of these systems include quick cure, pumpability, ease of use and lack of solvents. Data documenting the good heat stability, flame retardance, and improved compression set characteristics of the liquid silicone rubbers are presented. In addition, case histories will illustrate the primary benefit of reduced cost per finished part derived from the fast cycle times, lower energy requirements and automation available from this new technology.

High-Green-Strength Silicone Rubber

A high-green-strength silicone rubber has been developed which can be processed on equipment designed to handle organic rubber in the uncured state. This paper describes the processing of silicone rubber for curved radiator hose where green strength is needed. A correlation between green strength, room temperature Mooney viscosity, and plasticity has been established and found to be strict enough to allow green strength to be estimated from room temperature Mooney viscosity and plasticity data. Good shelf life along with excellent processing properties on a 2-roll mill are characteristic of this silicone rubber stock. Data will be presented covering handling properties, immersion tests, typical physical and thermal properties. Currently, this silicone rubber is being used in hose applications and could be considered for others where green strength is a requirement.