Oxidized Lignin Adhesive for Wood Bonding Strength and Moisture Resistance
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Solution Overview
Problem
Existing adhesives for lignocellulosic materials like wood often require harmful or corrosive components, are expensive, or have low resistance to heat and moisture, limiting their effectiveness and safety.
Innovation Solution
An aqueous adhesive composition comprising oxidized lignins as the main component, combined with cross-linkers such as β-hydroxyalkylamide or oxazoline-cross-linkers, and plasticizers like polyethylene glycols, which together provide strong bonding properties without harmful agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional adhesives (isocyanate-based, polyvinyl acetate-based, etc.) are used for lignocellulosic materials, then bonding strength or cost-effectiveness is improved, but harmful materials are used or resistance to heat and moisture deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the adhesive by using oxidized lignin with specific carboxylic acid group content (0.1-5 mmol/g) and combining it with specific cross-linkers (β-hydroxyalkylamides, oxazolines) and plasticizers (polyethylene glycols with specific molecular weights). This parameter optimization enables the adhesive to achieve high bonding strength while being free from harmful materials like isocyanates and formaldehyde.
Solution Approach 2:
The patent creates a composite adhesive system combining oxidized lignin (renewable polymer) with cross-linkers and plasticizers. This composite approach integrates the adhesive properties of lignin with the cross-linking capability of β-hydroxyalkylamides/oxazolines and the flexibility provided by polyethylene glycols, achieving both high strength and environmental safety.
2Ease of manufacture
If cheap adhesives like poly(vinyl acetate) are used, then cost is reduced, but resistance to heat and moisture deteriorates
Solution Approach 1:
The patent optimizes the chemical composition parameters including carboxylic acid group content (0.1-5 mmol/g), molecular weight of polyethylene glycols (200-20,000), and cross-linker ratios to achieve both cost-effectiveness and high resistance to heat and moisture. The use of renewable oxidized lignin as the base polymer keeps costs low while the cross-linking system provides durability.
3Reliability
If oxidized lignin with high carboxylic acid group content is used, then adhesive properties and resistance to heat/moisture are improved, but manufacturing complexity increases
Solution Approach 1:
The patent defines specific parameter ranges for oxidized lignin (carboxylic acid groups: 0.1-5 mmol/g) and other components to balance performance and manufacturability. These optimized parameters ensure high adhesive properties and resistance to heat/moisture while keeping the formulation simple enough for practical manufacturing.
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 adhesive composition achieves excellent mechanical properties and resistance to heat and moisture, while being inexpensive and free from corrosive or harmful materials, making it suitable for lignocellulosic materials.
Implementation Method 1
an aqueous adhesive composition for lignocellulosic materials such as wood comprising: a component (i) in form of one or more oxidized lignins; a component (ii) in form of one or more cross-linkers
Implementation Method 2
a method of producing a bonded lignocellulosic product which comprises the step of contacting one or more lignocellulosic materials with the adhesive and curing said composition
Data Source
AI summary
An aqueous adhesive composition for lignocellulosic materials which comprises a component (i) in the form of one or more oxidized lignins, a component (ii) in the form of one or more cross-linkers, and a component (iii) in the form of one or more plasticizers.