Electroless metallisation of microporous plastics film in metal ion soln. - giving mechanical stability, strong adhesion, corrosion resistance and high conductivity, e.g. for capacitor or thin film battery

摘要

In the metallisation of plastic films, microporous films (I) with a pore size of 5-1000 nm and thickness of 5-500 microns are subjected to electroless metallisation on one or both sides in a soln.of the corresp. metal ions. (I) pref. consists of (halogenated) polyolefin. (I) are pref. premetallised and then the metal film is enhanced by electroplating. (I) metallised on one side may also be electroplated on the back by rivet-like anchoring through the pore structure remaining on the back. In this case, the electroplating pref. extends through the pore structure on the back until the metal protrudes from the pores and beyond the plane of the surface of the film. USE/ADVANTAGE - The metallised films are useful for e.g. electrolytic capacitors and thin film batteries. They are mechanically stable and the metal adheres well, even in aggressive solns. and has high conductivity. In an example, hydrophobic microporous separator films e.g. `Celgard 24000' (RTM; pores sizes 20-50 and 100-200 microns; porosity 40%) were activated 1-5 min. at 40-45 deg. C in an activator soln. prepd. by dissolving 6 g/l NaOH and concn. `Neoganth' (RTM) soln. in an amt. giving 0.2 g/l Pd(2+), stirring 2 h at 50 deg. C, allowing to cool and adjusting to pH 10.5-11. After rinsing with water, redn. was carried out for a least 1 min. at room temp. in an aq. soln. of 1 g/l NaBH4, 5 g/l NaOH and 3 ml/l `FC 128' (RTM). The film was rinsed, then metallised 5 min. at 30-35 deg. C in an aq. Cu plating soln. contg. 40 ml/l `Naviganth HC' (RTM), 8 g/l NaOH, 0.4 ml/l stabiliser, 15 ml/l reducing agent soln. and 3 ml `FC 128' (RTM: fluorinated surfactant) soln. in MeOH, adjusted to pH 12.8-13. A thin, homogeneous, highly lustrous Cu film was formed on both sides, which was bonded well and max. 200 nm thick. The resistance was typically 1 k (in the lengthwise direction). This type of Cu plating did not impair the flexibility of the film. It was then electroplated with Cu, Ni, etc.