Printing screen cleaning and reclaiming compositions
AssigneeIntercontinental Chemical Corporation
InventorGary M. Valasek
Life of this patent
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Abstract
Ink cleaning compositions are disclosed which degrade or solubilize broad classes of printing ink residues on printing screens for quick removal by a pressurized water stream. The compositions are essentially non-aqueous and contain N-methyl-2-pyrrolidone (NMP), an oxygenated solvent, such as butyl cellosolve and cyclohexanone, and a surfactant. Alternatingly, compositions containing NMP and tetrahydrofurfuryl alcohol as the primary components are disclosed. Methods of cleaning and reclaiming printing screens which provide synergistic activities are also disclosed. The compositions meet health and safety standards due to their biodegradability, lack of flammability and high threshold limit values.
Claims24
A printing screen ink cleaning composition for removing inks from images on said screen and for performance at room temperature consisting essentially of a non-aqueous biodegradable liquid mixture of about 30 to 85% N-methyl-2-pryyolidone, about 10 to 35% of an oxygenated solvent and about 1-5% of a surfactant.
A method of cleaning a printing screen having a residue of ink on the surface thereof which comprises the steps of treating at room temperature the printing screen ink residue with a non-aqueous biodegradable liquid composition consisting essentially of about 30 to 85% of N-methyl-2-pyrrolidone, about 10 to 35% oxygenated solvent and about 1-5% surfactant,
- allowing the composition to dwell on the ink surface for a sufficient period of time to degrade the ink residue, and
- rinsing the degraded ink residue with a pressurized stream of water.
A method of cleaning and reclaiming a printing screen having a printed image of an emulsion and a residue of ink on the surface thereof which comprises the steps of
- treating at room temperature the printing screen ink residue with a non-aqueous biodegradable liquid composition consisting essentially of about 30 to 85% N-methyl-2-pyrrolidone, about 10 to 35% oxygenated solvent and about 1-5% surfactant,
- allowing the composition to dwell on the ink surface for a sufficient period of time to degrade the ink residue,
- rinsing the degraded ink residue with a pressurized stream of water,
- contacting within a short time the water-rinsed screen with a periodate-containing emulsion remover, and
- flushing the resultant screen with a stream of pressurized water to remove the emulsion image.
Dependencies are inferred from the claim text.