Flexographic ink containing a polymer or copolymer of a 3, 4-dialkoxythiophene

A method for preparing a non-dye containing flexographic ink, containing a polymer or copolymer of a 3,4-dialkoxythiophene in which the two alkoxy groups may be the same or different or together represent an optionally substituted oxy-alkylene-oxy bridge, a polyanion and a latex binder in an organic solvent or aqueous medium, characterized in that said polymer or copolymer of a 3,4-dialkoxythiophene is present in a concentration of at least 0.1% by weight in said ink and that said ink is capable of producing a colorimetrically additive transparent print, comprising the steps of:

• i) concentrating an aqueous dispersion of said polymer or copolymer of (3,4-dialkoxythiophene) and said polyanion;
• and iii) adding said latex binder.

A flexographic printing process comprising the steps of:

• providing a non-dye containing flexographic ink, containing a polymer or copolymer of a 3,4-dialkoxythiophene in which the two alkoxy groups may be the same or different or together represent an optionally substituted oxy-alkylene-oxy bridge, a polyanion and a latex binder in an organic solvent or aqueous medium, characterized in that said polymer or copolymer of a 3,4-dialkoxythiophene is present in a concentration of at least 0.1% by weight in said ink and that said ink is capable of producing a colorimetrically additive transparent print, printing said printing ink on an optionally subbed substrate thereby producing a colorimetrically additive transparent print.

A non-dye containing flexographic ink containing at least 0.1% by weight of a polymer or copolymer of a 3,4-dialkoxythiophene in which the two alkoxy groups may be the same or different or together represent an optionally substituted oxy-alkylene-oxy bridge, a polyanion and a latex binder in a solvent or aqueous medium and said ink is capable of producing a colorimetrically additive transparent print obtainable by a method for preparing a non-dye containing flexographic ink, containing a polymer or copolymer of a 3,4-dialkoxythiophene in which the two alkoxy groups may be the same or different or together represent an optionally substituted oxy-alkylene-oxy bridge, a polyanion and a latex binder in an organic solvent or aqueous medium, characterized in that said polymer or copolymer of a 3,4-dialkoxythiophene is present in a concentration of at least 0.1% by weight in said ink and that said ink is capable of producing a colorimetrically additive transparent print, comprising the steps of:

• i) concentrating an aqueous dispersion is of said polymer or copolymer of (3,4-dialkoxythiophene) and said polyanion;
• and iii) adding said latex binder.