Polyurethane Papermaking Belt With Silane-Treated Nanoparticle Dispersion
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Solution Overview
Problem
Existing papermaking process belts face challenges in suppressing fatigue crack growth rates, particularly due to secondary aggregation of nanoparticles in polyurethane compositions, which limits the use of higher nanoparticle blending ratios and affects hydrophilic properties required for certain applications.
Innovation Solution
Incorporating nano inorganic fillers with a silicon oxide component, treated with organic silane coupling agents, into the polyurethane composition to enhance dispersion and prevent secondary aggregation, thereby improving the fatigue crack growth suppression effect and hydrophilic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If nanoparticles are blended into polyurethane composition to suppress fatigue crack growth, then crack resistance is improved, but secondary aggregation occurs limiting the usable blending ratio
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance between the nanoparticles and polyurethane matrix. The silane coupling agent prevents secondary aggregation of nanoparticles while enhancing their dispersion stability in the polyurethane composition, thereby resolving the contradiction between crack resistance improvement and composition stability maintenance.
Solution Approach 2:
The patent optimizes the blending ratio of nanoparticles to polyurethane within a specific range (0.1-10 wt%), and controls the silane coupling agent content at 0.1-5 wt% relative to nanoparticles. By precisely controlling these compositional parameters, the patent achieves both improved fatigue crack growth suppression and maintained dispersion stability.
2Strength
If higher nanoparticle blending ratio is used to improve crack resistance, then fatigue crack growth suppression is enhanced, but hydrophilic properties deteriorate
Solution Approach 1:
The silane coupling agent serves as a mediator that maintains the hydrophilic properties of nanoparticles even at higher blending ratios. The coupling agent's molecular structure preserves the surface characteristics of inorganic fillers while preventing aggregation, thus maintaining hydrophilic functionality throughout the polyurethane matrix.
3Strength
If nanoparticles are added to enhance mechanical properties, then wear resistance is improved, but manufacturing complexity increases due to dispersion control requirements
Solution Approach 1:
The silane coupling agent simplifies the manufacturing process by providing a ready-made dispersant that prevents nanoparticle aggregation during mixing and processing. This intermediary substance eliminates the need for complex dispersion control procedures, making the manufacturing process more straightforward while maintaining wear resistance improvements.
4Stability of the object's composition
If polyurethane composition is cured by heating to form the belt, then structural integrity is achieved, but foaming occurs due to moisture reaction
Solution Approach 1:
The silane coupling agent acts as a protective intermediary layer between moisture and the polyisocyanate compound during curing. This coupling agent prevents direct reaction between moisture and isocyanate groups that would generate foam, while still allowing the curing process to proceed and achieve structural integrity.
Solution Approach 2:
The silane coupling agent is applied to nanoparticles beforehand to create a moisture-resistant surface layer before the curing process begins. This preliminary protective action prevents moisture from reacting with the polyisocyanate compound during heating, thereby preventing foaming while maintaining structural integrity.
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 approach results in a papermaking process belt with significantly improved hardness and fatigue crack growth rate suppression, offering 2 to 4 times better performance compared to commercially available polyurethane belts, while maintaining hydrophilic properties and preventing foaming during heat curing.
Implementation Method 1
enhance dispersion and prevent secondary aggregation
Implementation Method 2
the surface of the nano inorganic filler is treated with an organic silane coupling agent
Implementation Method 3
one part of the polyurethane or all of the polyurethane is formed by heat curing of a curable urethane composition comprising a urethane prepolymer which is obtained by reacting an aromatic isocyanate compound with polyol and has a terminal isocyanate group, and a curing agent having an active hydrogen group
Implementation Method 4
the moisture content of the nano inorganic filler is 1% by weight or less... preventing foaming during heat curing
Implementation Method 5
the surface of the nano inorganic filler is treated with an organic silane coupling agent having an active hydrogen group
Data Source
AI summary
A process belt for papermaking with a long operational life including an integrated structure of a reinforcing fibrous base material and a polyurethane layer is disclosed. The reinforcing fibrous base material is embedded in the polyurethane and the outer peripheral surface and the inner peripheral surface are made of the polyurethane. Nanoparticles including, as a main component, a silicon oxide component, the surface of which is treated with an organic silane coupling agent, are homogeneously dispersed in one part or all of the polyurethane.