PREPARATION METHOD OF PTFE COMPOSITE DISK FOR PRINTED CIRCUIT BOARD

摘要

PURPOSE: A method for preparing a PTFE (polytetrafluoroethylene) composite disk for a printed circuit board is provided, to obtain a PTFE composite disk having a low thermal expansion coefficient and a dielectric constant of 3.5 or less suitable for the frequency of GHz range. CONSTITUTION: The method comprises the steps of (10) soaking a glass fiber cloth in a water dispersion comprising 10-60 parts by weight of PTFE particles, 1-5 parts by weight of a surfactant and 100 parts by weight water; (20) drying the soaked cloth; (30) optionally removing moisture from the dried cloth by heating it at a temperature of 90-130 deg.C for 10-30 min; (40) increasing the temperature of the dried cloth to 250-300 deg.C to remove the surfactant, and cooling slowly it to prepare a prepreg; and (50) overlapping the prepregs and hot pressing the overlapped one at a temperature of 300-380 deg.C. Preferably the hot pressing is carried out with a pressure of 1-5 ton/m¬2. Preferably the soaking and drying processes are repeated 2-4 times.