凹版印刷用インキの流動特性と ... - dnp.co.jp

1 DNP Rheology and Flow Characteristics of Intaglio Inks S. Shinozaki, H. Yamaguchi, T. Suzuki, E. Miyata and M. Aritomi DNP Fine Chemicals Co., Ltd. ABSTRACT: On the basis of the flow behavioral analysis of offset inks, we found that factors (Yield, Viscous and Modulus terms) controlling the fluidity of offset inks and three power indexes(m,n and p) of our flow characteristic formula(formula ) are different at the share rate range from low to high. Sm n Gp S: Yield term : Viscous term G: Modulus term ; (m+n+p=1) We have tried to analyze mottling phenomena affecting significantly the printing quality of intaglio printings by using the rheological analysis. The mottling has been estimated quantitatively by using the digital image analysis, and also Yield, Viscous and Modulus terms have been measured and contribution ratio has been calculated.

2 We have concluded that the loss elastic modulus G plays a dominant role on the mottling phenomena. Therefore, it is conceivable that a high quality printing of gravure inks can be possible by controlling the G . 2 AR-G2 TA 12 (a) (b) Fig. 1. The mottling phenomenon; (a) the mottling print, (b) the non;mottling print.

3 (a) (b) Table 1. The amounts of additive and the area ratios of the dark and light of prints. Additive 1 (wt%)Additive 2 (wt%)Dark area (%)Light area(%)A003367B024456C125347D206139E0570 30F227327G258119 Commercial aqueous inka;;7129 Commercial aqueous inkb;;7822 Commercial aqueous inkc;;928 Commercial non;aqueousink a;;8317 Commercial non;aqueousink b;;8614 Additive1 Additive2 2 Terms Sign Calculation formula Yield term S From yield value 0 (steady flow measurements). S=log Viscous term From loss elastic modulus G (dynamic frequency;dependent measurements). =logG Elastic term G From storage elastic modulus G (dynamic time;dependent measurements). G=logG 12 formula 2 formula S0 = (log 0)0 (logG ) (logG ) formula 58 103 2010 1987 Table 2.

4 Calculation formula of rheological parameters. Relationship between the dark area ratio and the yield term. Relationship between the dark area ratio and the viscous term. Relationship between the dark area ratio and the elastic term. y = ; + = ;10;505 SThe dark area ratio / %y = ; + = ;202 The dark area ratio / %y = ; + = ;50510G The dark area ratio / %Fig. 5. Relationship between the dark area ratio and the flow characteristic value. y = ; + = ;10123S0 G' dark area ratio / %