{HEAD ~ A surprising feature} of the invention involves {TAIL ~ the discovery} that while the coating compositions of the invention are known to provide strong adhesive bonds to metal substrates, the same coatings have failed to provide bonds of satisfactory strength on synthetic plastic substrates 
involves
{ HEAD ~ A surprising feature } of the invention involves { TAIL ~ the discovery } that while the coating compositions of the invention are known to provide strong adhesive bonds to metal substrates , the same coatings have failed to provide bonds of satisfactory strength on synthetic plastic substrates
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