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US 5,609,671 AGranted
Water-based pigment ink and process for producing the same
AssigneeOrient Chemical Industries, Ltd.
InventorToshiyuki Nagasawa
Life of this patent
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Abstract
Water-based pigment ink having high concentration which provides excellent jetting stability when using for ink-jet printer and provides excellent writing stability when using for fine-point pen was provided. The water-based pigment ink comprises water and carbon black, wherein said carbon black has a surface active hydrogen content of not less than 1.5 mmol/g.
Claims17
Water-based pigment ink comprising water and carbon black, wherein said carbon black has a surface active hydrogen content of not less than 1.5 mmol/g.
A process for producing a pigment suitable for water-based pigment ink comprising the steps of:
- (a) providing acidic carbon black;
- and
- (b) oxidizing the acidic carbon black with a hypohalite salt in water.
Dependencies are inferred from the claim text.