Search Results

This paper describes work aimed at the development of toughened granular fiber reinforced phenolic molding compounds for use in high speed injection molding processes for the automotive industry. Two aspects of toughening were investigated, resin modification and fiber length and type. A proprietary impact modifier was studied to determine the effect of modifier level and glass fiber level on the toughness and flexural properties of short glass reinforced phenolic composites. To determine the effect of fiber length and type, a new proprietary compounding technique was developed to produce granular molding materials with fiber lengths previously attainable only in bulk molding compounds. New toughened phenolic composites were developed based on these studies and are compared to commercial composites based on unmodified and rubber toughened phenolic resins.

Parts made from phenolic molding materials must be postcured to promote the thorough crosslinking required for end usage at temperatures above about 175°C. Since the time and energy used in postcuring can represent about ten percent of part cost, efficient postcuring offers significant potential savings. Based on a kinetic description of the phenolic crosslinking reaction, we have developed a computer model to predict the development of the glass transition during postcure. This model provides a convenient CAD tool for minimizing postcuring costs.