Processing technology of poly (phthalamide)

Although other melting processes can be used, most PPA resins are processed by traditional injection molding processes. Pre-drying PPA raw materials to a humidity level below 0. 1%, and then putting them into heat-sealed metal village bags or boxes. These containers can ensure that PPA raw materials do not need to be dried before processing. The acceptable humidity level of processing technology is 0. 15% or lower. Processing wet resin will reduce the molecular weight and cause the corresponding loss of mechanical properties. Under the condition of175 f, it is easy to dry the resin until the dew point humidity is-25 f or even lower, and the drying time depends on the absorbed water, generally within the range of 4- 16 hours.

During injection molding, the melting temperature is in the range of 615-650 F, and the residence time of materials in the barrel is not more than 10 minute, which makes the mechanical properties of injection molded products the best. In order to obtain products with complete crystallization and optimal dimensional stability, the mold temperature is required to be at least 275 F. Due to the slow cooling rate, parts with partial thick walls can be injected at a lower mold temperature. Mold temperature is very important to optimize the surface inductance of finished parts. The mold surface temperature of mineral filler grade PPA resin used for vacuum plating metal into electroplated metal needs 350 degrees Fahrenheit.