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US 12,241,205 B2Granted
Thermosensitive paper
AssigneeRohm and Haas Company
InventorsBrian R. Einsla, Andrew Hejl, Ethan C. Glor, Junsi Gu
Life of this patent
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Abstract
The present invention relates to a coated paper article with an intermediate basecoat layer comprising high void fraction porous hollow sphere polymer particles (HISPs). HSPs with very small pore area density and high void fraction result in increased optical density at a given print energy in thermal printing applications.
Claims8
A coated paper article comprising:
- a) a 40-μm to 500-μm thick paper substrate;
- b) a 2-μm to 10-μm thick basecoat layer comprising porous multistage polymer particles and a binder;
- and
- c) a 1-μm to 30-μm thick thermosensitive recording layer;
- wherein the basecoat layer is disposed between the thermosensitive recording layer and the paper substrate;
- wherein the porous multistage polymer particles have a shell-hollow core morphology, and a number-weighted average particle size in the range of from 500 nm to 3 μm;
- wherein the shell comprises from 0.5 to 10 weight percent structural units of a salt of a carboxylic acid monomer, and from 90 to 99.5 weight percent structural units of styrene;
- wherein at least 98 weight percent of the shell comprises structural units of styrene and the salt of the carboxylic acid monomer;
- and
- wherein the porous multistage polymer particles have a pore area percent in the range of from 0.005 to 0.5 percent of the surface area of the multistage polymer particles as determined by the measurement method described herein.
7 more elements
Dependencies are inferred from the claim text.