Single-Layer Paperboard Coating with Low Density Organic Pigments
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Solution Overview
Problem
Existing paperboard coatings require multiple layers to achieve superior smoothness and printability, often involving hyperplaty clay, and struggle to achieve high quality at low coat weights.
Innovation Solution
A single-layer coating using a combination of low-density organic pigments (LDOP) and inorganic pigments, such as coarse ground calcium carbonate, applied at low coat weights, achieves superior smoothness and printability, with Parker PrintSurf values of 2.5 microns or lower, and improved ink gloss similar to double-coated products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a single-layer coating is used, then coat weight is reduced, but smoothness and printability deteriorate
Solution Approach 1:
The coating combines low-density organic pigment (LDOP) particles with inorganic pigment particles in a synergistic formulation. The LDOP provides bulk and void volume for smoothness, while the inorganic pigment contributes to surface quality and printability, achieving superior results at low coat weights through material composition rather than layer multiplication
Solution Approach 2:
The invention changes the particle size distribution parameters of the pigment blend, specifically using LDOP with controlled density and size ranges (0.5-2.0 microns) combined with inorganic pigment particles of complementary sizes. This parameter optimization allows a single layer to achieve the smoothness typically requiring multiple layers
2Manufacturing precision
If multiple coats are applied, then smoothness and printability improve, but coat weight and complexity increase
Solution Approach 1:
The invention merges the functions of multiple coating layers into a single integrated coating formulation. The base coat and top coat functionalities are combined into one application, eliminating the need for sequential coating operations while maintaining superior printability through the LDOP-inorganic pigment synergistic formulation
Solution Approach 2:
The single-layer coating formulation performs multiple functions simultaneously: it provides surface smoothing, creates print-receptive properties, and achieves appropriate gloss characteristics, replacing what traditionally required separate specialized layers
3Manufacturing precision
If hyperplaty clay is used, then smoothness improves, but formulation complexity and cost increase
Solution Approach 1:
The invention replaces expensive, specialized hyperplaty clay with a more economical combination of LDOP and common inorganic pigments. This substitution achieves comparable or superior smoothness through particle physics rather than relying on rare, expensive clay minerals
Solution Approach 2:
The invention changes the formulation approach by controlling particle size distribution and density ratios in the LDOP-inorganic pigment blend, replacing the need for hyperplaty clay's unique layered structure with a statistically optimized particle assembly that achieves similar surface properties
Data Source
AI summary
Coatings are disclosed which provide single-layer-coated paperboard having good smoothness and printability. Low density organic pigments (LDOP) are used in some of the coatings. Certain coatings when applied as single-layer coatings at 6 lb/3000 ft2 (9.8 g/m2) and higher gave Parker PrintSurf values less than 2.5 microns. Certain coatings when applied as base coats and then top coated gave PrintSurf values less than 2.0 microns for uncalendered samples.