Flexible electrically conductive pastes and devices made therewith

An article comprising:

• an electrical circuit containing an electrically conductive entity formed from a polymer thick film electrically conductive paste composition comprising:
• (a) conductive metal powder;
• (b) resin blend of polyol and phenoxy resin, both of which contain hydroxy groups (OH);
• (c) blocked aliphatic polyisocyanate which contains isocyanate groups (NCO);
• and
• (d) one or more polar, aprotic solvents, wherein the resin blend and the blocked aliphatic polyisocyante are dissolved in the one or more solvents and the metal powder is dispersed in the one or more solvents,
• and wherein said paste composition has been cured.

A method of attaching an electrical circuit element having at least one terminal to a substrate having first and second major surfaces and a conductive trace on the first surface, comprising the steps of:

• (a) providing an injection mold composed of a plurality of mating portions that, when assembled, together define an interior cavity adapted to receive molten plastic material that is appointed to be formed onto the substrate;
• (b) depositing a compliant electrically conductive adhesive on at least one of the at least one terminal or a connection point of the conductive trace that is appointed to be electrically connected to the terminal;
• (c) assembling the injection mold with the substrate and the circuit element enclosed therein, with the circuit element being situated on the first surface with the at least one terminal being in registration with the connection point and in contact with the electrically conductive adhesive;
• (d) thereafter filling the interior cavity with a molten plastic material;
• and
• (e) solidifying the plastic material and thereafter removing the substrate
• and the circuit element attached thereto from the injection mold, and wherein the cavity is configured such that, when solidified, the plastic material at least partially embeds the circuit element and secures it to the substrate with the at least one terminal electrically connected to the conductive trace.

A circuit assembly comprising:

• (i) at least one electrical circuit element having at least one terminal and (ii) a substrate having first and second major surfaces and a conductive trace pattern on the first surface, wherein the at least one terminal and the conductive trace are electrically connected through an electrically conductive adhesive comprising a polymer thick film electrically conductive paste composition interposed therebetween;
• said paste composition comprising:
• (a) a conductive metal powder;
• (b) a resin blend of polyol and phenoxy resin both of which contain hydroxy groups (OH);
• (c) a blocked aliphatic polyisocyanate which contains isocyanate groups (NCO);
• and
• (d) one or more polar, aprotic solvents, wherein the resin blend and the blocked aliphatic polyisocyanate are dissolved in the one or more solvents and the metal powder is dispersed in the one or more solvents.