Method of producing a modified diisocyanate,method of producing a self-lubricating enamelling varnish and method of producing an enameled electrical conductor

1 - 10 . (canceled)

11 . A process for preparing a modified diisocyanate to which is attached a pendant aliphatic chain containing at least 15 carbon atoms, said process for obtaining said modified diisocyanate comprising the steps of:

reacting an isocyanate functional group of a triisocyanate with a terminal functional group of an aliphatic chain; and

carrying out said preparation of the modified diisocyanate in a solvent medium with stirring and heating.

12 . The process for preparing a modified diisocyanate as claimed in claim 11 , wherein said terminal functional group is selected from alcohols, anhydrides, carboxylic acids and amines.

13 . A process for preparing a self-lubricating insulating varnish having a modified polymer comprising a base polymer to which is attached a pendant aliphatic chain containing at least 15 carbon atoms, said process comprising the following steps:

preparing a modified diisocyanate as claimed in claim 11; and

mixing said modified diisocyanate with at least one difunctionalized monomer containing two second functional groups which are reactive with the first isocyanate functional groups of the modified diisocyanate, to carry out said synthesis of said modified polymer.

14 . The process for preparing a self-lubricating insulating varnish as claimed in claim 13 , wherein said base polymer is a polyamide-imide.

15 . The process for preparing a self-lubricating insulating varnish as claimed in claim 13 , wherein said base polymer is selected from polyurethanes, polyamides, polyesters, polyester-imides, solderable polyester-imides, polyester amide-imides, polyimides, polyepoxide compounds and polyphenoxide compounds.

16 . The process for preparing a self-lubricating insulating varnish as claimed in claim 13 , wherein said base polymer is a semiaromatic polyamide and wherein the so-called anchor group attaching the base polymer to said pendant aliphatic chain is a urethane or an amide, such that said self-lubricating insulating varnish is thermally adhering.

17 . The process for preparing a self-lubricating insulating varnish as claimed in claim 13 , wherein, said base polymer being a polyurethane, the process further comprises a step of mixing the modified polyurethane with a polymer selected from a solderable polyester-imide and a modified solderable polyester-imide.

18 . The process for preparing a self-lubricating insulating varnish as claimed in claim 13 , wherein a difunctionalized monomer containing two functional groups similar to the isocyanate functional groups of the modified diisocyanate is mixed with said modified diisocyanate.

19 . A process for producing an enameled electrical conductor, said process comprising the steps of:

preparing the self-lubricating insulating varnish as claimed in claim 13; and

coating an electrical conductor with a layer of the self-lubricating insulating varnish.