Bio-Based Polyurethane Shoe Press Roll Casing for Crack Resistance
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Solution Overview
Problem
Existing shoe press roll shells in the paper industry are environmentally unsustainable due to high petroleum-based material consumption and require frequent replacement, with mechanical properties that can be improved.
Innovation Solution
Develop a polyurethane matrix material for shoe press roll shells that is at least 20% bio-based, using specific combinations of bio-based polyols and crosslinkers to enhance mechanical properties while reducing environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional petroleum-based polyurethane is used for shoe press roll shells, then mechanical properties are maintained, but environmental sustainability deteriorates due to high CO2 emissions and material consumption
Solution Approach 1:
The patent changes the chemical composition parameters of the polyurethane matrix by substituting petroleum-based polyols with bio-based polyols (such as those derived from vegetable oils or sugar). This parameter change maintains the polyurethane's mechanical properties while reducing the carbon footprint, as bio-based materials sequester atmospheric CO2 during plant growth. The specific formulation uses bio-based polyols in combination with conventional isocyanates to achieve both sustainability and performance requirements.
Solution Approach 2:
The patent creates a composite material system combining bio-based polyols with conventional isocyanates and crosslinkers to form a polyurethane matrix. This composite approach allows the beneficial environmental properties of bio-based materials to be integrated while maintaining the mechanical performance through the synergistic combination with proven conventional components. The reinforcing threads or fabrics are embedded in this composite matrix to achieve the required strength and durability.
2Object-affected harmful factors
If shoe press roll shells are made from bio-based polyurethane, then environmental sustainability is improved, but mechanical properties may deteriorate
Solution Approach 1:
The patent optimizes the molecular weight, hydroxyl value, and chemical structure parameters of the bio-based polyols to match the performance characteristics of conventional petroleum-based polyols. By carefully selecting and formulating bio-based polyols with appropriate parameters, the resulting polyurethane achieves comparable tensile strength, elongation, and abrasion resistance. The formulation may include specific ratios of different bio-based polyols to achieve the desired mechanical property profile.
3Reliability
If shoe press roll shells require frequent replacement due to wear, then operational reliability is maintained, but material consumption and environmental impact worsen
Solution Approach 1:
The patent modifies the polyurethane matrix parameters to enhance wear resistance, tear resistance, and crack propagation resistance. This involves optimizing the crosslinking density, molecular structure, and hardness parameters of the polyurethane to match or exceed the durability of conventional materials. The improved durability reduces the frequency of replacement, thereby reducing total material consumption and environmental impact over the operational lifecycle.
Data Source
AI summary
The invention relates to a shoe press roll casing for a machine for production and/or finishing of a fibrous web, such as a paper, card or tissue web, comprising a matrix material composed of polyurethane, formed essentially from 4,4'-MDI as isocyanate, at least one polyol and at least one crosslinker, wherein the polyurethane matrix material is biobased to an extent of at least 20% by weight, wherein the at least one polyol and the at least one crosslinker are selected from one of the following combinations: a) PTMEG as polyol and a mixture of MCDEA and PTMEG as crosslinker, wherein the PTMEG in the polyol and in the crosslinker is biobased; b) polycarbonate as polyol and a mixture of MCDEA and polycarbonate polyol as crosslinker, wherein the polycarbonate polyol in the crosslinker is biobased; c) a mixture of polycarbonate polyol and PTMEG as polyol and 1,4-BDO as crosslinker, wherein the polycarbonate polyol in the polyol is biobased; d) PTMEG as polyol and a mixture of PTMEG and MCDEA as crosslinker, wherein the 4,4'-MDI in the isocyanate and the PTMEG in the polyol are biobased. The invention further relates to a shoe press having such a shoe press roll casing, and to a machine for production and/or finishing of a fibrous web with such a shoe press.