Papers by Author: Kai Yuan Luo

Abstract: In order to investigate the effects of fillers on the transfer properties of UV waterless offset ink, four ink samples compound with different fillers(SiO₂ , CaCO₃ and Talc) were prepared, the flow curve, thixotropy and ink transferred ratio were tested, and the effects of rheological properties on ink-transfer were discussed. The results show that: all of four ink samples show a typical shear thinning characteristics. Sample use SiO₂ and CaCO₃ as fillers has a higher viscosity, and with the increase of shearing rate, the viscosity decreased sharply. Sample use SiO₂ and CaCO₃ as fillers has the minimum thixotropic area, and the minimum thixotropy. Sample use SiO₂ and Talc as fillers has the largest thixotropic area, and the largest thixotropy. Sample use SiO₂ and CaCO₃ as fillers has the highest ink transfer ratio.

Abstract: Curing rate is one of the most important performance parameters of UV curing system. During the curing process, curing degree is closely related to curing rate. Cross linking and curing degree of the system could be reflected by rheological characteristics. A method based on rheokinetics was used to characterize radical polymerization reaction which initiated by UV light. Changes of G’ (dynamic modulus) in every stage of curing process were real-time monitored by a rheometer equipped with UV curing accessory. The influence of varieties and contents of photo-initiators on curing process of polyester acrylates was studied. Associating conversion rate with dynamic modulus, a nonlinear kinetic equation was set up to describe the cure reaction. The results show that, this paper has put forward a method based on rheokinetics, to study the curing rate of UV curing system, and provided a new approach to study UV cure reaction.

Abstract: In order to investigate the influence of filler on the rheological properties of UV curable offset ink, ink samples with various varieties and contents of fillers were prepared, the flow curve, thixotropy, dynamic and viscoelastic properties have been tested, and the rheological properties UV offset ink samples with various varieties and contents of fillers have been discussed. The results indicated that: variety and content have great influence on the rheological properties of ink samples. Sample use SiO₂ as filler has the highest viscosity, the largest thixotropy and G’; Sample use SiO₂as filler has the lowest viscosity, the largest thixotropy, while it’s G’ has no big difference from the sample use CaCO₃. Along with the increase of filler content, the viscosity, thixotropy and G’ will increase.

Abstract: There is more and more wide application of UV offset ink in green printing and packaging areas. The offset ink is emulsified inevitably and it will cause a great influence on the ink properties. UV offset ink samples prepared with different prepolymers. Base on the measurements of flow curve, thixotropy and dynamic viscoelastic properties under different emulsification ratio to explore the influence of emulsification on the rheological properties of UV offset ink as well as the effect on the rheological properties with different prepolymers at maximum emulsification ratio. The results indicated that the ink viscosity, thixotropy and dynamic viscoelastic properties decline as the increase of emulsification ratio. Compared with polyester prepolymer ink sample that the emulsified ink sample with epoxy prepolymer shows a faster declined in viscosity, lower thixotropy and larger G’ value. This variation trends relate to the viscosity and net structure of the emulsified ink system.