Publication Date: 2001-Jul-09
The IP.com Prior Art Database
A composition comprising: a) 0.1 to 30 parts of colorant; b) 0.1 to 20 parts of a compound of Formula (1):
This invention relates to inks, to printing processes, to printed substrates and to ink-jet printer cartridges.
Ink-jet Printing ("IJP") is a non-impact printing technique in which droplets of ink are ejected through a fine nozzle onto a substrate without bringing the nozzle into contact with the substrate. There are many demanding performance requirements for inks used in IJP. For example they desirably provide sharp, non-feathered images having good water-fastness, light-fastness and optical density. The inks are often required to dry quickly when applied to a substrate to prevent smudging, but they should not form a crust over the tip of an ink-jet nozzle because this will stop the printer from working. The inks should also be stable to storage over time without decomposing or forming a precipitate which could block the fine nozzle. Stability is a particular issue when jetting is performed at temperatures in excess of 30oC where problems can arise, especially with regard to pH drift which in turn results in destabilisation of the ink formulation leading to problems such as crystallisation and colour shift.
Inks containing reactive dyes for use in textile ink-jet printing are known from US Patent No. 5,403,358. The inks are buffered to pH 5 to 8 using the sodium salt of metanilic acid (i.e. aniline-3-sulphonic acid) or an alkali metal phosphate.
According to a first aspect of the present invention there is provided a composition comprising:
a) 0.1 to 30 parts of colorant;
b) 0.1 to 20 parts of a compound of Formula (1):
R1 is H, alkyl, cycloalkyl or aralkyl and R2 is alkyl, cycloalkyl or aralkyl; or
R1 and R2, together with the N atom to which they are attached, form a 5- or 6- membered ring;
Ar is phenylene or naphthylene;
X is H or a cation; and
n is 1 or 2;
c) 1 to 40 parts of organic solvent;
d) 0 to 20 parts of hydrotropic agent;
e) 0 to 5 parts of biocide;
f) 0 to 5 parts of surfactant; and
g) 1 to 98.8 parts of water;
wherein all parts are by weight and a) b) c) d) e) f) +g) add up to 100.
a) The Colorant
Preferably the colorant comprises a dye. Preferred dyes are azo, anthraquinone, pyrroline, phthalocyanine, polymethine, aryl-carbonium, triphenodioxazine, diarylmethane, triarylmethane, anthraquinone, phthalocyanine, methine, polymethine, indoaniline, indophenol, stilbene, squarilium, aminoketone, xanthene, fluorone, acridene, quinolene, thiazole, azine, nigrosine, oxazine, thiazine, indigoid quinonioid, quinacridone, lactone, pyrroline, benzodifuranone, or indolene dyes and mixtures thereof. Preferred azo dyes are monoazo, disazo and trisazo dyes.
Preferably the dye is a reactive dye, more preferably a dye having a reactive group selected from halotriazine (especially mono- or di- chloro or fluorotriazine), vinyl sulphone, groups convertible to vinyl sulphone on treatment with aqueous alkali (especially (-sulphatoethyl sulphonyl) and halo pyrimidine (especially 1,3,4-trichloro pyrimidin-2-yl, 1,3-difluoro-4...