A Novel Solvent-Less Approach to Manufacture Pre-Pregs and Laminates with Improved Dimensional Consistency for Electronic Applications

本研究项目将基于连续树脂传递模塑或注射拉挤的概念，研究一种新的无溶剂工艺。目前用于制造电子预浸料和层压板的工艺使用的是溶剂型系统。溶剂对环境不友好，对工人构成潜在危险，也不会增加最终产品的价值。溶剂正受到越来越多的管制，预计到2000年，许可证费用将翻一番。溶剂也可能是缺陷的来源，如果预浸料干燥得太快，就会形成空洞。在这个封闭系统中，工艺的核心是浸渍/B分段模，在那里可以使用高压来促进树脂浸渍到玻璃纤维织物中。在更传统的方法中，层压板是由铜箔和多层预浸料材料构成的，批处理过程会通过固化过程中的温差引起变异性。注射拉挤工艺将是一个连续的直插式层压工艺，它允许真空技术以及用空气以外的气体对模腔进行注水，以最大限度地减少或消除空隙。还将研究引入填料以改善性能的情况。预计随着浸渍工艺的改进和缺陷的减少，该工艺将能够以更少的空隙制造出尺寸更一致的预浸料。尺寸一致性是提高打印机电路板致密性的关键因素，对于减少电路板车间的内部套准废品，从而降低成本和避免浪费至关重要。

This research project will investigate a new solvent-less process, based on the concept of continuous Resin Transfer Molding or Injection Pultrusion. Current processes used to manufacture electronic pre-pregs and laminates use solvent-based systems. Solvents are environmentally unfriendly, pose potential hazards to workers and add no value to the final product. Solvents are being increasingly regulated with permit costs expected to double by the year 2000. Solvents can also be the source of defects, with voids forming if the pre-preg is dried too rapidly. In this closed-system, the heart of the process is the impregnation/B-staging die, where high pressures can be used to promote resin impregnation into the glass fabric. In more traditional approaches, where the laminate is constructed from copper foils and multiple layers of pre-preg materials, the batch process can induce variability through temperature differences during curing. The injection pultrusion process will be a continuous in-line lamination process that allows vacuum techniques as well as flooding of the die chamber with gases other than air in order to minimize or eliminate voids. The introduction of fillers to improve properties will also be investigated. It is expected that with the improved impregnation and reduced defects, this process will allow the manufacture of more dimensionally consistent pre-pregs with fewer voids. Dimensional consistency is a key enabler for increased densification of printer circuit boards and is critical to decreasing internal registration scrap at the board shops, thus reducing costs and avoiding waste.