Journal of Applied Polymer Science, Vol.82, No.3, 601-610, 2001
Application of chemo-rheology to establish a process window for a new solventless system to manufacture pre-pregs and laminates for electronic applications
The most common commercial processes for manufacturing pre-pregs for electronic applications use solvent-based epoxy systems. Solvents are environmentally unfriendly and contribute to voids in the pre-preg and laminate. Voids cause product variability, which is a major source of scrap in board shops. In this paper, we use chemo-rheological and kinetic measurements to identify a potential epoxy-based resin system for a solventless process that is based on injection pultrusion. Differential scanning calorimetry and rheological data show that the candidate system does not react appreciably without catalyst up to temperatures of 170 degreesC or with catalyst at temperatures < 110 degreesC. The system solidifies at temperatures < 105 degreesC. The overall viscosity of the resin system is dependent on the temperature, degree of cure, and filler content. Kinetic rate and viscosity rise expressions to be used in process modeling and optimization have been developed. A preliminary process window for the process is established.