Erasable ink composition containing a graft-polymerized dye

Claim 2

An erasable ink composition which comprises: a) a water-insoluble polymer dye obtained by the graft polymerization of a preformed water-insoluble polymer with an ethylenically unsaturated dye monomer; and, b) an evaporable liquid carrier for the polymer, the erasable ink composition when applied to a substrate and upon drying thereon exhibiting less than about 30 weight percent flaking based on the weight of the dried ink and an erasability value delta E*ab of less than about 4.0.

Claim 3

The erasable ink composition of claim 1 exhibiting less than about 20 weight percent flaking based on the weight of the dried ink and an erasability value delta E*ab of less than about 3.5.

Claim 4

The erasable ink composition of claim 1 exhibiting less than about 10 weight percent flaking based on the weight of the dried ink and an erasability value delta E*ab of less than about 3.0.

Claim 5

The erasable ink composition of claim 1 wherein the carrier is an aqueous liquid, the polymer dye being dispersed therein.

Claim 6

The erasable ink composition of claim 1 wherein the polymer dye possesses an average particle size of from about 25 to about 1000 nanometers.

Claim 7

The erasable ink composition of claim 1 wherein the polymer dye possesses an average particle size of from about 50 to about 250 nanometers.

Claim 8

The erasable ink composition of claim 9 wherein the composition possesses a viscosity of at least about 500,000 centipoises.

Claim 9

The erasable ink composition of claim 1 wherein the water-insoluble polymer is derived from one or more olefinically unsaturated monomers such as ethylene, propylene, butadiene, isobutylene, isoprene, vinyl chloride, vinyl esters, vinyl ethers, acrolein, acrylic esters, methacrylic esters, acrylamides, methacrylamides, acrylonitrile and methacrylonitrile, one or more cyclic compounds such as lactones, lactams,cyclic ethers, cyclic sulfides, cyclic amines, polycaprolactones, polycaprolactams, polyethyleneimines and poly(3,3-bis-chloromethyl)-oxetane, polycondensates such as phenol resins, urea resins, melamine resins and alkyd resins, polyesters such as those derived from terephthalic acid and ethylene glycol, polycarbonates, polyamides such as those derived from adipic acid and hexamethylenediamine, unsaturated polyesters, polyaddition resins such as polyurethanes and epoxy resins, and natural and semisynthetic polymers such as cellulose, chemically modified cellulose and natural rubbers.

Claim 10

The erasable ink composition of claim 1 wherein the preformed water-insoluble polymer is provided as an aqueous emulsion of a water-insoluble vinyl polymer.

Claim 11

The erasable ink composition of claim 1 wherein the dye monomer is an ethylenically unsaturated compound of the general formula ##STR3## wherein DYE represents a dye residue, X 1 and X 2 each represents a bridging group covalently linking the dye residue to the ethylenically unsaturated group(s), R 1 , R 2 , R 3 , R 4 , R 5 and R 6 each is hydrogen or halogen or an aliphatic or aromatic group of up to about 12 carbon atoms, unsubstituted or substituted with one or more halogen atoms and/or one or more hydroxyl, sulfhydryl, carboxylic acid, amino, nitro, alkoxy, alkoxycarbonyl or cyano groups, a is 1 to 5, b is 1 to 5 and c is 0 or 1.

Claim 12

The erasable ink composition of claim 10 wherein DYE is derived from a yellow dye such as 1-phenylthio-5-(3'-methacryloylamidothiophenyl)-anthraquinone, 1-(3'-methacryloylamidophenylthio)-anthraquinone or 1-(4'-tertbutylphenylthio)-5-(3'-methacryloylamidophenylthio)-anthraquinone, a blue dye such as 4-amino-1,8-dihydroxy-2,7-diisobutyl-5-methacryloyl-amidoanthraquinone or 4-amino-1,8-dihydroxy-2,7-diisopropyl-5-methacryloylamidoanthraquinone, 4-amino-1,5-dihydroxy-2,6-diisobutyl-8-methacryloylamidoanthraquinone, a cyan dye such as N-(3'-methacryloylamidopropyl) 1,4-diaminoanthraquinone-2,3-dicarboximide, N-(6'-methacryloylamidohexyl) 1,4-diaminoanthraquinone-2,3-dicarboximide or N-(6'-methacryloylhexyl) 1,4-diaminoanthraquinone-2,3-dicarboximide, a purple dye such as N-(3'-methacryloylpropyl) 1-amino-4-methacryloylamidoanthraquinone-2,3-dicarboximide, a magenta dye such as 1-amino-4-hydroxy-2-(N-3'-methacryloylpropylamino)-anthraquinone, 1-amino-4-hydroxy-2-(N-3'-methacryloylhexylamino)-anthraquinone, 1-amino-4-hydroxy-2-(N-3'-methacryloylamidohexylamino)-anthraquinone or 1-amino-4-hydroxy-2-(3'-methacry-loylhexylthio)-anthraquinone, or a red dye such as 1,5-dihydroxy-2,6-diisobutyl-4-(3'-methacryloylamidophenylthio)-anthraquinone, 1,8-dihydroxy-2,7-diisobutyl-4-(3'-methacryloylamidophenylthio)-anthraquinone, 1,5-dihydroxy-2,6-diisobutyl-4-methacryloylamidoanthraquinone, 1,8-dihydroxy-2-7-diisobutyl-4-methacryloylamidoanthraquinone, 1,8-dihydroxy-2,7-diisopropyl-4-methacryloylamidoanthraquinone or 1,4,5-triphenylthio-8-(3'-methacryloylamido-phenylthio)-anthraquinone.

Claim 13

The erasable ink composition of claim 10 wherein the bridging groups X 1 and X 2 include the groups --NHCO--, --OCNH--, .paren open-st.OC) 2 N--, --NHR 7 OOC-- and --N(R 7 OOC.paren close-st. 2 in which R 7 is an aliphatic group of up to about 12 carbon atoms, and --X 3 R 8 (OOC.paren close-st. d in which X 3 is --O--, --COO-- or --NH--, R 8 is an aliphatic group of up to about 12 carbon atoms, optionally containing at least one ester linkage, and d is equal to a in the case of bridging group X 1 and to c in the case of bridging group X 2 .

Claim 14

The erasable ink composition of claim 10 wherein the preformed water-insoluble polymer is provided as an aqueous emulsion of a water-insoluble vinyl polymer.

Claim 15

The erasable ink composition of claim 1 further comprising at least one component selected from the group consisting of natural latices, synthetic latices, rheological modifiers, suspension agents, humectants, emulsifiers, surfactants, plasticizers, spreading agents, drying agents, release agents, parting agents, preservative, antimicrobial agents, anticorrosion agents, antioxidants and coalescing aids.

Claim 16

A marking instrument containing the erasable ink composition of claim 1.

Claim 17

The marking instrument of claim 15 which is a ball-point pen.