Hollow Polymeric Pigment Coating for Paper Stiffness
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Solution Overview
Problem
Conventional paper coating compositions struggle to achieve high gloss and smoothness while maintaining the stiffness and bulk of coated papers, often resulting in permanent deformation of the base paper during calendering, which compromises the paper's strength and opacity.
Innovation Solution
The use of a paper coating composition with a high level of hollow polymeric pigment, ranging from 35 to 65 parts per 100 weight parts total pigment, which minimizes base paper compaction during calendering, allowing for high gloss and smoothness while retaining the paper's original stiffness and bulk properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional paper coating compositions are used to achieve high gloss and smoothness through calendering, then the coating surface quality is improved, but the base paper undergoes permanent deformation resulting in loss of stiffness, bulk, and strength
Solution Approach 1:
The patent changes the chemical composition parameters of the coating by incorporating reactive silane-modified polymers and specific clay minerals (talc, pyrophyllite, or sepiolite) in controlled ratios. This chemical parameter change allows the coating to achieve high smoothness through chemical bonding rather than mechanical compression, thereby avoiding base paper deformation and maintaining stiffness
Solution Approach 2:
The patent creates a composite coating material combining silane-modified polymers with specific clay minerals (talc, pyrophyllite, or sepiolite). This composite structure provides both the smoothness needed for high-quality printing and the structural integrity to prevent base paper deformation during calendering, resolving the contradiction between surface quality and paper strength
2Illumination intensity
If harsh calendering is applied to achieve high gloss finish, then the coating surface quality is improved, but the base paper loses opacity, stiffness, and strength
Solution Approach 1:
The patent modifies the coating composition parameters by incorporating light-scattering clay minerals (talc, pyrophyllite, or sepiolite) alongside silane-modified polymers. This parameter change enables the coating to achieve high gloss through controlled light reflection on a stable surface, rather than through harsh mechanical compression that would compromise base paper opacity
Solution Approach 2:
The silane-modified polymer acts as an intermediary between the clay minerals and the base paper. It creates a stable, chemically-bonded coating layer that provides the smooth surface needed for high gloss while protecting the base paper from direct mechanical stress during calendering, thereby preserving opacity
3Strength
If high levels of hollow polymeric pigment are used to minimize base paper compaction, then the paper's original stiffness and bulk properties are retained, but achieving high gloss and smoothness becomes more difficult
Solution Approach 1:
The patent combines hollow polymeric pigment with silane-modified polymers and clay minerals in a composite coating system. The hollow pigment particles provide stiffness and bulk, while the silane-modified polymer matrix and clay minerals work together to create a smooth surface through chemical bonding, resolving the contradiction between maintaining paper properties and achieving coating smoothness
Solution Approach 2:
The patent applies different functional components to different aspects of the coating: hollow polymeric pigment for structural properties (stiffness/bulk), silane-modified polymer for chemical bonding and surface smoothness, and clay minerals for light scattering and surface stability. This local quality assignment allows each component to optimize its specific function without compromising overall performance
Data Source
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AI summary
Embodiments of the present disclosure include paper coating compositions, coated paper and/or paperboard, and methods of forming coated paper and/or paperboard with the paper coating compositions. The embodiments of the paper coating compositions contain high levels of hollow polymeric pigment relative to other pigments used in the paper coating composition (e.g., inorganic pigments). The paper coating compositions can provide the coated paper and/or paperboard with a wide variety of desirable features (e.g., high gloss, good smoothness, improved stiffness), while minimizing compaction (i.e., permanent deformation) of the underlying base paper.