Lignin-Based Adhesive for Cryogenic Plywood Panels
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Solution Overview
Problem
Plywood panels used in cryogenic applications, such as LNG tankers, face issues with adhesive brittleness at low temperatures, leading to reduced mechanical properties and potential structural failures.
Innovation Solution
A plywood panel design utilizing a lignin-based adhesive with a high proportion of polymerizable substance from lignin, combined with hardwood veneers and cross-lamination, which enhances the panel's resistance to thermal deformation and mechanical strength at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional adhesive is used in plywood panels, then the panel can be manufactured with standard materials, but the adhesive becomes brittle at low temperatures and mechanical properties deteriorate
Solution Approach 1:
The adhesive composition is modified by changing the polymerizable substance ratio to at least 50 wt%, with specific molecular weight distribution (100-1000 Da: 10-40 wt%, 1000-10000 Da: 30-70 wt%, >10000 Da: 10-40 wt%). This parameter optimization prevents brittleness at low temperatures while maintaining bonding strength.
Solution Approach 2:
The adhesive uses a composite resin system combining polymerizable substances from lignin with specific molecular weight distributions. This composite structure provides both low-temperature flexibility and bonding strength, resolving the contradiction between adhesive reliability and panel strength at cryogenic temperatures.
2Strength
If hardwood veneers are used instead of softwood, then the panel density and strength increase, but the weight of the panel increases
Solution Approach 1:
Hardwood veneers are selectively used in specific layers where higher strength is required, while maintaining overall panel weight efficiency. The cross-lamination structure distributes stress locally, allowing optimized material placement.
Solution Approach 2:
The combination of hardwood veneers with the optimized lignin-based adhesive creates a composite structure where the high density and strength of hardwood are effectively utilized. The adhesive's molecular weight distribution ensures strong bonding that充分发挥s the hardwood's mechanical properties while minimizing unnecessary weight.
3Stability of the object's composition
If cross-lamination with different grain orientations is used, then thermal deformation resistance improves, but manufacturing complexity increases
Solution Approach 1:
The plywood panel is divided into multiple veneer layers with alternating grain orientations (0°, 90°, 0°, 90° pattern). This segmentation approach distributes thermal stress across layers, preventing deformation while maintaining a standardized manufacturing process that isn't overly complex.
Solution Approach 2:
The cross-laminated hardwood veneers bonded with the optimized lignin-based adhesive create a composite structure that resists thermal deformation. The specific adhesive composition (with controlled molecular weight distribution) ensures strong inter-layer bonding that maintains structural integrity during temperature variations, balancing performance with manufacturability.
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 lignin-based adhesive and hardwood veneer configuration result in a plywood panel that maintains its mechanical properties and resistance to thermal treatments, making it suitable for cryogenic applications without significant strength reduction.
Implementation Method 1
an adhesive comprising resin comprising some polymerizable substance, wherein a certain proportion of the polymerizable substance originates from lignin
Data Source
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Figure 3a~3d
Figure 4a~4f
AI summary
A plywood panel (100) for use at a temperature of less than minus 50 °C, the plywood panel (100) comprising a first, a second, and a third veneer layer (110, 120, 130) comprising hardwood, the veneer layers (110, 120, 130) having been attached to each other with adhesive (200) comprising resin. The resin (a) comprises polymerizable substance and crosslinking agent, wherein (b) at least 50 weight-% of the polymerizable substance originates from lignin, (c) at least 10 % of the molecules in the resin have a molecular weight of above 10000 Da, (d) at least 10 % of the molecules in the resin have a molecular weight of below 1000 Da, (e) a number-average molar mass of the resin is from 1000 Da to 1600 Da, and (f) a weight-average molar mass of the resin is from 5000 Da to 14000 Da. A method for manufacturing such a plywood panel (100). A use of such a plywood panel (100) at a low temperature. A cargo containment system (CCS), such as a ship (400), comprising such a plywood panel (100).