Disclosed is a process of improving the adhesion of polyester material to various other materials using the azidoformates of omega-hydroxyalkyl phthalates, their related low molecular weight condensation polymers and their mixtures represented by the general formula ##SPC1## Where R is an alkylene radical containing 2 to 10 carbon atoms and x is an integer of from about 1 to about 10. In particular, there is disclosed a process of improving the adhesion of polyester tire cord to rubber tire stock using the said azidoformate compounds.
This application is a division of copending application Ser. No. 231,741, filed Mar. 3, 1972, now U.S. Pat. No. 3,814,657, which application is a division of application Ser. No. 93,399, filed Nov. 27, 1970, now U.S. Pat. No. 3,686,231, which application is a continuation-in-part of application Ser. No. 887,382, filed Dec. 22, 1969, now abandoned.
For surface modification of natural or synthetic macromolecular substrates, organic compounds are used that have hydrophilic, hydrophobic, oleophobic, ionic and/or cross-linkable groups and that also have groups which are easily convertible to nitrene or carbene, e.g., azide or diazo groups. Such organic compounds are applied to the surface to be modified as a monolayer or oligolayer from a solution thereof and then are photochemically activated. Conditions which cause orientation of the molecule with the azide or diazo group toward the surface of the substrate are advantageous. The other cross-linkable groups may promote diagonal cross-linking of the applied layer.
