Low Density Paperboard Coating for Smooth Surface
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Solution Overview
Problem
Conventional methods for producing low density paperboard with a smooth surface require increasing the paperboard density, which is undesirable and costly, while also failing to achieve the desired smoothness for high-quality printing.
Innovation Solution
A low density paperboard is created by applying a coating to a fiber substrate, forming a coated structure with a Parker Print Surf smoothness of at most 3 microns, and maintaining a specific basis weight calculated using various equations, which includes a fiber substrate and optional topcoat, to achieve the desired smoothness without increasing density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If wet stack calendering process is used to achieve smooth surface, then surface smoothness is improved, but paperboard density increases
Solution Approach 1:
The patent applies a coating to the paperboard surface before final calendering to create a smooth surface layer. This preliminary coating application allows the subsequent calendering process to smooth the coating rather than compressing the entire paperboard structure, achieving smoothness without excessive density increase
Solution Approach 2:
The invention creates a localized smooth surface layer through coating application, rather than requiring uniform compression of the entire paperboard. The coating provides the smooth quality locally at the surface while the bulk paperboard maintains its low density structure
2Manufacturing precision
If paperboard density is increased to achieve smooth surface, then surface smoothness is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the approach from modifying bulk density to modifying surface properties through coating. By applying a coating layer and calendering that layer, the process achieves smoothness without requiring high bulk density, thereby reducing material costs and manufacturing expenses
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively provides a smooth paperboard with low density, suitable for high-quality printing, while reducing manufacturing costs by maintaining a low basis weight and caliper thickness, achieving significantly lower densities compared to prior art while maintaining smoothness.
Implementation Method 1
a coating applied to the fiber substrate to form a coated structure... the coated structure having a Parker Print Surf smoothness of at most about 3 microns
Data Source
AI summary
A paperboard including a solid bleached sulfate paperboard substrate and a coating applied to the paperboard substrate to form a coated structure, the coated structure having a basis weight, a caliper thickness and a Parker Print Surf smoothness, the Parker Print Surf smoothness being at most about 3 microns, the basis weight being at most about Y1 pounds per 3000 ft2, wherein Y1 is a function of the caliper thickness (X) in points and is calculated as follows: Y1=3.79+13.43X−0.1638X2.