Protecting metal reinforcements adhering to rubber against corrosion - by short pretreatment with aq. alkali nitrite solns.

摘要

Metallic reinforcements for adhesion to rubber mixts., esp. steel cord reinforcements for pneumatic tyres, are protected against corrosion by pre-treatment with an aq. soln. of alkali nitrite, esp. NaNO2 and KNO2. Treatment is short, taking only the time needed for wetting. Soln. Concn. may be 1% to cold saturation, e.g. for brass- or bronze-plated steel cord, and pref. 10-15% for Zn-plated steel cord. The pre-treated materal is dried at up to 150 degrees C. Treatment prevents corrosion of both brass-, bronze- or Zn-plated as well as non-plated steel cord. E.g. brass -plated streel cord pre-treated with 10% NaNO2 soln. resisted 300000 flexures (De Mattia test) followed by 4 hrs. immersion in water, whereas an untreated cord rusted right through.