Near infrared absorbing fine particle dispersion liquid and method for producing the same, anti-counterfeit ink composition using near infrared absorbing fine particle dispersion liquid, and anti-counterfeit printed matter using near infrared absorbing fine particles

摘要

Provided are a near infrared absorbing fine particle dispersion liquid having an absorption ability in a near infrared region, a clear contrast, and applicable to offset printing, and a method for producing the same, an anti-counterfeit ink composition using the near infrared absorbing fine particle dispersion liquid and an anti-counterfeit printed matter using near infrared absorbing fine particles. Also provided are a near infrared absorbing fine particle dispersion liquid containing a solvent of one or more kinds selected from vegetable oils or vegetable oil-derived compounds; near infrared absorbing fine particles in an amount of 2 mass % or more and 25 mass % or less, selected from one or more kinds of hexaboride fine particles expressed by a general formula XB_a (wherein element X is at least one or more kinds selected from a group consisting of La, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Y, Sm, Eu, Er, Tm, Yb, Lu, Sr, and Ca, satisfying 4.0≤a≤6.2); and a dispersant soluble in the solvent and having a fatty acid in its structure, wherein viscosity is 180 mPa/S or less, and an anti-counterfeit ink composition containing the near infrared absorbing fine particle dispersion liquid. Also provided is an anti-counterfeit printed matter excellent in anti-counterfeit effect due to the printed matter containing the near infrared absorbing fine particles.