Single pass radiation curable inkjet printing methods for producing printed flexible foils and plastic bags
View Patent ↗A radiation curable inkjet printing method for producing printed flexible foils and plastic bags wherein a web-like polymeric substrate having a maximum value for Tan δ between 40° C. and 110° C. and a surface energy S sub is printed upon using a single pass inkjet printer with a non-aqueous radiation curable inkjet liquid having a surface tension S Liq , wherein S Liq is smaller than S sub by at least 4 mN/m, and curing the radiation curable liquid on the substrate at a surface temperature equal or higher than the temperature of the maximum value for Tan δ and smaller than the melting point of the polymeric recording medium. A single pass inkjet printer is also disclosed.
1. A radiation curable inkjet printing method comprising the steps of:
providing a polymeric substrate having a maximum value for Tan δ between 40° C. and 110° C.;
providing a single pass inkjet printer including at least one page-wide printhead or at least one set of staggered printheads, a transporting device arranged to transport the polymeric substrate, and a curing device;
jetting onto the polymeric substrate, having a surface energy S sub , a non-aqueous radiation curable inkjet liquid having a surface tension S Liq , wherein S Liq is smaller than S Sub by at least 4 mN/m; and
curing the non-aqueous radiation curable inkjet liquid on the polymeric substrate at a surface temperature equal to or higher than a temperature of the maximum value for Tan δ and smaller than a melting point of the polymeric substrate; wherein
the maximum value for Tan δ is determined by dynamic mechanical analysis at a temperature ramp of 3° C./min using forced oscillation with a cycle of 1 second and an amplitude of 100 μm.
2. The radiation curable inkjet printing method according to claim 1 , wherein the curing device is a UV curing device, and a heat produced by the UV curing device is used to create a surface temperature of at least 50° C. on the polymeric substrate.
3. The radiation curable inkjet printing method according to claim 2 , wherein the surface temperature is in the range of 50° C. to 100° C.
4. The radiation curable inkjet printing method according to claim 1 , wherein the non-aqueous radiation curable inkjet liquid is a pigmented radiation curable inkjet ink.
5. The radiation curable inkjet printing method according to claim 1 , further comprising the step of printing a pigmented radiation curable inkjet ink on the non-aqueous radiation curable inkjet liquid.
6. The radiation curable inkjet printing method according to claim 5 , wherein a surface tension of the pigmented radiation curable inkjet ink is not more 5 mN/m smaller than the surface tension of the non-aqueous radiation curable inkjet liquid.
7. The radiation curable inkjet printing method according to claim 1 , further comprising the step of providing a corona treatment to the polymeric substrate.
8. The radiation curable inkjet printing method according to claim 1 , wherein the polymeric substrate includes a primer layer, and a thickness of the primer layer is less than 5 μm.
9. The radiation curable inkjet printing method according to claim 1 , wherein the polymeric substrate is a polyethylene substrate.