Durable and Flexible Ink Composition for High-Quality/High-Definition Screen Printing, Printed Product Obtained by Screen Printing Said Ink Composition, and Manufacturing Method for Said Printed Product

An ink composition for screen printing to be used onto a thermoplastic resin substrate, comprising:

• an ink composition adapted to produce printed matter comprising both a solid image pattern and a fine image pattern with the spreading width of no more than 10 μm from image design dimensions of a printing plate at one of edges and outlines of any section in a printed image, when producing printed matter by screen printing onto a thermoplastic resin substrate using a 360-mesh screen printing plate formed by a high-strength, non-deforming stainless steel mesh with a filament diameter of 25 μm,
• the ink composition having a measured flow radius value between 13.0 to 24.0 mm after 1 minute from a start of measurement by a flow property measuring method using a spread meter at 25° C. according to JIS K5701-1:2000,
• the ink composition satisfying an inequality “F60”−“F45”≦1.0 mm, wherein “F60” is defined as the measured flow radius value after 1 minute and “F45” is defined as the measured flow radius value after 45 seconds from the start of measurement by the flow property measuring method using the spread meter,
• the ink composition having a viscosity of 5 to 180 Pa·s as measured with a BH-type rotating viscosimeter at 25° C.,
• the ink composition having a thixotropic index (TI value) of 2.0 to 8.0,
• the ink composition including a solvent which is selected from one or more solvents from the group consisting of butylcellosolve acetate, dialkyl adipate ester, isophorone, 3-methoxy-3-methylbutanol, 3-methoxy-3-methylbutyl acetate, coal tar naphtha with a boiling point of not less than 170° C., diethyleneglycol monoethyl ether, diethyleneglycol monoethyl ether acetate, diethyleneglycol monobutyl ether, triethyleneglycol monobutyl ether, triethyleneglycol monobutyl ether acetate, (meth)acrylate monomer, vinyl ether monomer and amide monomer, with a boiling point of not less than 170° C. at not less than 70 mass % of a total of the solvent,
• the ink composition including a thermoplastic polymer with a weight-average molecular weight of not less than 4000 and with a Tg (softening point) of 20 to 95° C. at not less than 10 mass % with respect to a total of the ink composition, and that can produce printed matter,
• wherein a printed image coating film has an elongation percentage of not less than 250% under vacuum forming or pressure forming.