US 7,842,162 B1 · Layer-by-layer nanocoating for paper fabrication

Abstract

A method is provided for manufacturing paper by means of layer-by-layer nanocoating techniques. The method comprises the sequential processing of an aqueous pulp of lignocellulose fibers which is first subjected to nanocoating by alternatively adsorbing onto the fibers multiple consecutively-applied layers of oppositely-charged nanoparticles, polymers and/or proteins thereby making a modified aqueous pulp of multi-layer nanocoated lignocellulose fibers, then draining the water out of the modified pulp to form sheets of multi-layer nanocoated fibers, and drying the formed sheets of multi-layer nanocoated fibers. The resulting dried sheets are then processed to make a finished paper that has superior physical strength and improved surface properties. In a preferred embodiment the starting aqueous pulp of lignocellulose fibers is divided into is separate portions which are separately nanocoated with opposite charges, and then blended to form a complex aggregate pulp of nanocoated fibers before draining and drying it. The method is particularly applicable to the treatment of broken (mill broke) recycled fibers in order to facilitate their usage in paper production.

Claims33

Dependent claims

A method for making paper with enhanced strength, comprising:

(a) forming a pulp of lignocellulose fibers;
(b) nanocoating said pulp of lignocellulose fibers by alternatively adsorbing onto the fibers multiple consecutively-applied layers of oppositely-charged nanoparticles and polymers, thereby making a modified pulp of multi-layer nanocoated lignocellulose fibers;
(c) draining the modified pulp to form one or more sheets of multi-layer nanocoated lignocellulose fibers;
(d) drying said formed one or more sheets of multi-layer nanocoated lignocellulose fibers;
and
(e) processing the dried nanocoated sheet or sheets to make a finished paper having enhanced strength and surface properties.

3 more elements

A process for manufacturing paper or paper board with enhanced strength and surface properties by means of self-assembly layer-by-layer nanocoating techniques in a plurality of sequential unit operations, said process comprising:

(a) nanocoating a first aqueous pulp of lignocellulose fibers having between about 0.5 and 15% solids by alternatively adsorbing onto the fibers multiple consecutively-applied layers of oppositely-charged polymers having a thickness of between about 5 and 100 nanometers, thereby making a first positively-charged modified aqueous pulp of multi-layer nanocoated lignocellulose fibers, said first positively-charged modified aqueous pulp comprising between about 30 and 70% of the total volume of pulp being processed;
(b) nanocoating a second aqueous pulp of lignocellulose fibers having between about 0.5 and 15% solids by alternatively adsorbing onto the fibers multiple consecutively-applied layers of oppositely-charged nanoparticles having a thickness of between about 5 and 100 nanometers, thereby making a second negatively-charged modified aqueous pulp of multi-layer nanocoated lignocellulose fibers, said second negatively-charged modified aqueous pulp comprising between about 30 and 70% of the total volume of pulp being processed;
(c) blending said first positively-charged modified pulp of nanocoated fibers with said second negatively-charged modified pulp of nanocoated fibers to form a complex aggregate pulp of nanocoated fibers;
(d) draining the water out of the complex aggregate pulp to form sheets of multi-layer nanocoated lignocellulose fibers;
(e) drying said formed sheets of multi-layer nanocoated lignocellulose fibers;
and
(f) processing the dried nanocoated sheets to make a finished paper having enhanced strength and surface properties.

4 more elements

Dependencies are inferred from the claim text.

Layer-by-layer nanocoating for paper fabrication

Life of this patent

Layer-by-layer nanocoating for paper fabrication

Life of this patent

Abstract

Claims33