GB675753A - Improvements in or relating to pastes for printing electrical circuit elements - Google Patents

Abstract

A printing paste for printing electric conductor elements contains finely-divided metallic particles, e.g. of silver, dispersed in a hydrophilic liquid also containing 0.1-0.5 per cent by weight of the liquid of a wetting agent comprising a sulphonated aliphatic alcohol containing more than six carbon atoms or the sodium salt of such a sulphonated alcohol, e.g. sulphonated lauryl alcohol; the liquid may be water. For printing electric resistance or semi-conductive elements, the metal may be replaced by a metallic oxide, e.g. cadmium oxide and the liquid may be glycerine. Specifications 569,388, 646,921, [both in Group II], 651,780 and 675,752, [both in Group XXXVI], are referred to.ALSO:Electric circuit conductor elements are printed by means of a paste containing finely divided metallic particles disposed in a hydrophilic liquid also containing 0.1-0.5 per cent by weight of the liquid of a wetting agent comprising a sulphonated aliphatic alcohol containing more than six carbon atoms or the sodium salt of such a sulphonated alcohol. Resistive or semi-conductive elements are printed by means of a similar paste in which the metallic particles are replaced by particles of metallic oxides. Silver for making a conductive paste may be prepared by adding powdered ammonium formate to a solution of silver nitrate and gelatine in water, heating the solution at 80-100 DEG C until the reaction is complete, separating the silver centrifugally, removing excess gelatine therefrom by agitating violently at 60-80 DEG C with distilled water and again centrifuging. The wet silver so separated is made into a paste with the required liquid, a little gelatine and 0.1-0.5 per cent of sulphonated lauryl alcohol or the sodium salt thereof. A resistive paste may comprise cadmium oxide, formed by reaction betwen cadmium sulphate, chloride or nitrate and sodium carbonate and heating the cadmium carbonate as formed; glycerine, gelatine and wetting compound. The base on which the elements are printed may be polystyrene-impregnated paper. Specifications 569,388, 646,921, 651,780 and 675,752, [both in Group XXXVI], are referred to.