Functional paper for electronics printing and methods of making
Provided herein is an uncoated functional paper formed from a slurry comprising about 10 wt % to 90 wt % cellulosic fibers and about 1% to 25% sizing solution per total weight of the fibers. The sizing solution can be applied during papermaking and/or applied in a size press or coater. The paper can be calendered at a temperature greater than 50° C. Methods of making are also provided. Also provided are flexible electronics including a functional paper substrate printed with a conductive ink.
1 . A method of making a functional paper comprising:
forming a paper from a slurry, the slurry comprising about 10 wt % to 90 wt % cellulosic fibers and about 1% to 25% sizing solution per total weight of the fibers;
calendering the paper at a temperature greater than 50° C. and a pressure between 100 psi and 1500 psi;
printing on the paper with a conductive ink wherein the calendering can be performed before printing, after printing, or both;
applying an internal sizing agent at a wet end of a paper machine; and
applying a surface sizing solution at a dry end of the paper machine using a size press,
wherein the surface sizing solution is selected from an aqueous solution comprising 10% solids by weight, wherein the solids comprise about 90 wt % ethylated starch and 10 wt % NaCl or wherein the solids comprise about 85 wt % ethylated starch, 10 wt % NaCl and 5 wt % acrylic copolymer.
2 . The method of claim 1 , further comprising applying the surface sizing solution to the paper using a rod coater to form sized and treated sheets.
3 . The method of claim 2 , wherein the surface treatment comprises a film-forming material in an aqueous medium, wherein the film-forming material is selected from ethylated starch, alginate, carboxymethyl cellulose (CMC), SBR latex (SBR), polyvinyl alcohol, and combinations thereof.
4 . The method of claim 2 , wherein the surface treatment further comprises one or more additives, wherein the additives are selected from a salt, a surface sizing agent, or a combination thereof.
5 . The method of claim 4 , wherein the surface sizing agent comprises acrylic copolymer or a copolymer of styrene and maleic anhydride.
6 . The method of claim 4 , wherein the salt is selected from a monovalent salt, a divalent salt, a multivalent salt, and a combination thereof, and wherein the surface treatment comprises about 10 wt % salt.