Patent ID: 7825108

Claim:
A method of printing an IR-absorbing dye onto a substrate whilst minimizing visible coloration of the substrate, said method comprising: (i) preselecting said dye from a metal-cyanine of formula (I): wherein: Q 1 , Q 2 , Q 3 and Q 4 are the same or different and are independently selected from a C 3-20 arylene group or a C 3-20 heteroarylene group; M is selected from Si(A 1 )(A 2 ), Ge(A 1 )(A 2 ), Ga(A 1 ), Al(A 1 ), Mn(A 1 ), Fe(A 1 ), Sn(A 1 )(A 2 ), Pb(A 1 )(A 2 ); A 1 and/or A 2 is a pentaerythritol derivative (A), a triethanolamine derivative (B), a phloroglucinol derivative (C), or a 3,5-dihydroxybenzyl alcohol derivative (D): P 1 is selected from the group consisting of: (CH 2 CH 2 O) y R 6 , wherein v is an integer from 2 to 5000 and R 6 is H, C 1-6 alkyl or C(O)C 1-8 alkyl; SO 3 Z, PO 3 Z 2 , C 1-12 alkyl-CO 2 Z, C 1-12 alkyl-SO 3 Z, C 1-12 -alkyl-PO 3 Z 2 , C 1-12 alkyl-OSO 3 Z or C 1-12 -alkyl-OPO 3 Z 2 , wherein Z is H or a water-soluble cation; and C 1-12 -alkyl-N + (R a )(R b )(R c ) or C 1-12 alkyl-U, wherein R a , R b , R c may be the same or different and are independently selected from H, C 1-8 alkyl, C 6-12 arylalkyl or C 6-12 aryl, and U is pyridinium, imidazolinium or pyrrolinium; and (ii) printing said dye onto said substrate.