Aqueous ink compositions containing anti-curl agents

Claim 1

A process for reducing paper curl in plain-paper printed elements consisting essentially of the step of applying an ink composition to a plain-paper substrate, said ink composition comprising an aqueous carrier medium, a colorant and at least one anti-curl agent in an amount sufficient to substantially eliminate curl in said plain-paper substrate, wherein the anti-curl agent has a solubility in water of at least 4.5% at 25° C. and is selected from the group consisting of: (a) 1,3-diols, 1,3,5-triols, amino-1,3-diols and polyoxyalkylene derivatives thereof having the following structure: ##STR5## wherein R 1 , R 2 , R 4 , R 5 and R 6 are independently H; C n H 2n+1 , where n=1-4; or C n H 2n O(CH 2 CHYO) b H where n=1-6 and b=0-25; R 3 =H; C n H 2n+1 where n=1-4; C n H 2n O(CH 2 CHYO) b H where n=1-6 and b=0-25; or (CH 2 ) e NXZ, where X and Z are independently H, CH 3 , C 2 H 5 or C 2 H 4 O(CH 2 CHYO) d H, where d=0-25 and e=0-3; Y=H or CH 3 ; a and c are independently 0-25; and wherein the total number of CH 2 CHYO units is 0-100; (b) polyols and oxyalkylene derivatives thereof having the following structure: ##STR6## wherein R is independently H, C n H 2n+1 , where n=1-4 or CH 2 O(CH 2 CHYO) e H; Y=H or CH 3 , b=0 or 1; a, c, d and e are independently 0-40, f=1-6; and wherein the total number of CH 2 CHYO units is 0-100; with the proviso that when a, b, c and d=0, and f=1, R is not H and when a, c, and d=0 and b and f=1, then R is CH 2 O(CH 2 CHYO) e H and e is not 0; (c) compounds having the following structure: ##STR7## wherein X=H; OH; CH 2 O(CH 2 CHYO) a H; O(CH 2 CHYO) b H; or OM where M is a metal cation; n=2-7; R=(CH 2 CHYO) c H, where Y=H or CH 3 ; a, b and c are independently 0-25; and wherein the total number of CH 2 CHYO units is 0-125; (d) pyranosides and polyalkoxyalkylene derivatives thereof having the following structure: ##STR8## wherein R=H or C n H 2n+1 , where n=1-4 a, b, c and d are independently 0-30; Y=H or CH 3 ; and wherein the total number of CH 2 CHYO units is 0-120; (e) poly (oxyalkylene) compounds having the following structure: H--(OCH.sub.2 CHY).sub.x OH wherein Y=H or CH 3 , and x=3-20; and (f) polyoxyalkylene derivatives of aliphatic polyamines having the structure: Z.sub.1 Z.sub.2 N(CH.sub.2 CH.sub.2 NZ.sub.3).sub.n Z.sub.4 wherein Z 1 , Z 2 , Z 3 , or Z 4 are independently (CH 2 CHYO) a H wherein Y=H or CH 3 ; n=1-20; a is independently 0-20; and wherein the total number of CH 2 CHYO units is 3-200.