Copper migration in the adhesive of NBR (acrylonitrile-butadiene copolymer) /epoxy resin blend system for flexible printed circuit board (FPC) is discussed by using the techniques of optical microscope, X-ray analytical microscope, transmission electron microscope, and ion chromatography. The accelerated migration test of FPC by the applied direct current voltage of 100V was carried out at 120°C under 100 % relative humidity. Because of high contents of inorganic anions such as SO₄^2- in the NBR domain of the adhesive, migrated copper ions from anode selectively precipitated as fine particles of copper oxides in the NBR domain. Copper ions reached to the cathode without precipitating in the NBR domain deposited as dendrites in the vicinity of the cathode.

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The effect of the water for the weathering of five kinds of polymers and two kinds of painting film were studied by using metal-halide lamp system. After the exposure of the weathering conditions, color difference, gloss, appearance change and surface layer cutting force patterns were observed. The article concludes as follows. (1) There was the effect of water on the degradation of ABS, PVC and melamine-alkyd paint in the weathering conditions. (2) The degradation of PC, PBT, PP and acrylic urethane coating was not influenced by the addition of water during the exposure. (3) The water condensation on the surface of paint during the exposure affects the properties of the surface. This effect is significantly higher than that of water spray. It is important to compare the effect of water spray and water condensation to evaluate the effect of water in weathering test.

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