Preparation of high‐tack value adhesive for offset printing inline cold foil stamping and its performance characterization

Abstract

A high‐tack‐value adhesive for offset printing inline cold foil stamping was prepared using rosin‐modified phenolic resin, terpene resin, industrial soybean oil, and solvent oil. The prepared adhesive can overcome the low accuracy of cold foil stamping and reproduction of existing conventional adhesives. The tack value, viscosity, ink (adhesive) thread length, ink flow, viscoelasticity, thixotropy, emulsification rate, and solid content of the prepared adhesives were characterized. The adhesive was applied on a MAN ROLAND 700 eight‐color offset printing cold foil stamping press. Stamping quality was evaluated. Results showed that the prepared adhesive has high tack value and the increment of the tack value is small with increasing test time. To achieve good stamping quality, the tack value of the adhesive should be controlled between 20 to 30, and its viscosity and emulsification rate should be kept at approximately 80 Pa·s and within the range of 30% to 40%, respectively. Appropriate levels of viscoelasticity, thixotropy, and ink flow were also necessary. POLYM. ENG. SCI., 59:139–144, 2019. © 2018 Society of Plastics Engineers