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US 2003/0193554 A1Published application
Aqueous colorant preparation for inkjet printing
AssigneeNone recorded
InventorsJames Bullock, Michael Krapp, Karl Siemensmeyer
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AssigneeNone recorded
InventorsJames Bullock, Michael Krapp, Karl Siemensmeyer
Estimating the term…
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The use is described of an aqueous colorant preparation including colloidally dispersed colorant particles and at least one dispersant selected from sulfonated and/or sulfomethylated lignins having a weight average molecular weight of not less than 25000 wherein more than 50% by weight of the lignins have a molecular weight of more than 10000, for printing sheetlike substrates by means of inkjet printing.
The use of an aqueous colorant preparation including colloidally dispersed colorant particles and at least one dispersant selected from sulfonated and/or sulfomethylated lignins having a weight average molecular weight of not less than 25000 wherein more than 50% by weight of the molecules have a molecular weight of more than 10000, for printing sheetlike substrates by means of inkjet printing.
The use of any of the preceding claims, wherein the dispersant is selected from sulfonated and/or sulfomethylated lignins having a polydispersity index PDI in the range from 7 to 11.
The use of any of the preceding claims, wherein the colorant is a disperse dye.
A process for printing sheetlike substrates, which comprises spraying an aqueous colorant preparation in droplets onto the substrate, the colorant preparation including colloidally dispersed colorant particles and at least one dispersant selected from sulfonated and/or sulfomethylated lignins having a weight average molecular weight of not less than 25000 wherein more than 50% by weight of the molecules have a molecular weight of more than 10000.
A method of producing a colorant preparation, which comprises grinding a colorant in the presence of a dispersant selected from sulfonated and/or sulfomethylated lignins having a weight average molecular weight of at least 25000 wherein more than 50% by weight of the molecules have a molecular weight of more than 10000 to form a millbase including colorant particles having a median particle size of less than 1 μm and diluting the millbase with water and optionally additional assistants to form a colorant preparation having a colorant content of from 0.1 to 20% by weight.
An aqueous colorant preparation useful for inkjet printing, including colloidally dispersed colorant particles having a median particle size of less than 1 μm and at least one dispersant selected from sulfonated and/or sulfomethylated lignins having a weight average molecular weight of not less than 25000 wherein more than 50% by weight of the molecules have a molecular weight of more than 10000.
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This invention relates to the use of an aqueous colorant preparation including colloidally dispersed colorant particles and a dispersant for printing sheetlike substrates by means of inkjet printing.
In inkjet printing, typically aqueous inks are uniformly pressed through a nozzle in small droplets and sprayed directly onto the substrate. Inks used in the inkjet printing process have to meet a whole series of requirements. They have to have a viscosity and surface tension suitable for printing, they have to be stable on storage, ie. they should not coagulate and the dispersed colorant should not sediment, and they must not clog up the printer nozzle.
Inks based on dispersed colorants (eg. pigments, disperse dyes and vat dyes) for inkjet printing, ie. inkjet inks, are generally produced in a two-step process. In the first step, the colorant is ground with a dispersant and optionally further assistants in a high-speed mill to produce a paste. In the second step, the ink is produced by diluting the paste with water and optionally further customary assistants.
The invention is illustrated by the inventive and comparative examples hereinbelow.
The following dispersants were used:
D1 is a sulfonated lignin having a weight average molecular weight of 30500 and a polydispersity index of 8.8, wherein 56.5% by weight of all the molecules have a molecular weight of more than 10000.
Containing carbon black: characterised by the pigment dispersant
Non common dispersing agents: anionic dispersing agents
Inks: inkjet printing inks
Pigment pastes, e.g. for mixing in paints: in aqueous medium
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