PP is prepreg that is to connect the inner layer and offer the insulation
PP (prepreg)Â is a kind of base materials of Printed Circuits Board.
It is an un-curable resin with non-conductive, which using for connecting the inner layer and offer the insulation.
Following is a 4 layers PCB stackup which including two pieces of 0.07 mm 1080 pp, there the 1080 pp is to connect top layer with 2 layer,and connect bottom layer with 3 layer, meanwhile pp is non-conductive.
pp in 4 layers PCB stackup
It consists of glass fiber and resin. The resin is un-curable status, called- B-Stage.
 Basic Types of PP
 Glass fiber types: 1080，2116，7628; list the normal thickness FYI:1080 pp:3 mil; 2116 pp: 4.2 mil; 7628 pp:7 mil;
Resin types: Phenolic Resin, Epoxy Resin, Polyimide Resin ,PI, Bismaleimide Triazine, BT
PP is for FE4 PCB, so if you wound like to know more about other PCB, for example Ceramic PCB, MCPCB, meanwhile don’t hesitation to contact us if any question.
