High-Filler Polyurethane Adhesive with Rapeseed Oil Ester
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Solution Overview
Problem
Moisture-curing polyurethane compositions with high filler content face challenges in maintaining mechanical properties and application stability, as excessive filler content leads to low elongation at break, processing difficulties, and potential premature curing due to water reactivity, making them unsuitable for extensible applications and manual application.
Innovation Solution
A moisture-curing composition with a filler content of at least 70% by weight, comprising 5-20% isocyanate-functional polymer and 7-20% rapeseed oil methyl ester, which maintains good mechanical properties and processing ease in the fully cured state, while being cost-effective and stable during storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If filler content is increased to reduce cost and improve mechanical properties, then production cost decreases and strength increases, but elongation at break decreases and processing becomes difficult
Solution Approach 1:
The patent applies parameter changes by carefully controlling the filler content within a specific range (50-80 wt%) rather than using excessive filler. It also adjusts the isocyanate index (NCO:OH ratio) to 80-150% and controls moisture content below 0.5%, optimizing multiple parameters simultaneously to achieve both high strength and good processability.
Solution Approach 2:
The patent uses composite materials by combining polyurethane polymers with inorganic fillers (such as calcium carbonate, silica, or aluminum oxide) in optimized proportions. This composite approach allows the filler to enhance strength while the polyurethane matrix maintains elasticity and processability, resolving the contradiction between strength and ease of operation.
2Quantity of substance
If filler content is increased to reduce cost, then production cost decreases, but composition stability deteriorates due to water reaction
Solution Approach 1:
The patent applies preliminary anti-action by pre-drying the filler to reduce moisture content below 0.5% before mixing with the polyurethane polymer. This preventive measure stops water from reacting with isocyanate groups during storage, preventing premature curing and maintaining composition stability even with high filler content (50-80 wt%).
Solution Approach 2:
The patent optimizes the isocyanate index (NCO:OH ratio) to 80-150%, which provides a buffer against moisture variations. This parameter optimization ensures that even if some water is present in the filler, the composition remains stable during storage and only cures properly when exposed to atmospheric moisture during application.
3Quantity of substance
If filler content is increased to improve cost-effectiveness, then production cost decreases, but application properties deteriorate due to extreme thickening
Solution Approach 1:
The patent optimizes filler content to a specific range (50-80 wt%) rather than using maximum possible filler. This parameter optimization balances cost-effectiveness with application properties, ensuring the composition remains pumpable and applicatable from cartridges or manual guns while still achieving high filler loading for cost reduction.
Solution Approach 2:
The patent uses a composite structure where inorganic fillers are dispersed in a polyurethane polymer matrix. This composite approach allows the organic polymer phase to act as a lubricant and flow agent, maintaining good application properties even with high filler content, while the inorganic filler provides cost-effectiveness and mechanical reinforcement.
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 composition achieves high elongation at break and easy processing, ensuring stability and suitability for applications like wood flooring adhesives and elastic sealants, with low extrusion force and improved storage stability, even after high-temperature storage.
Implementation Method 1
In the majority of cases this is atmospheric moisture, reacting with the reactive polyurethane constituents of the compositions and resulting in the crosslinking and the full curing of the composition.
Data Source
AI summary
A moisture-curing composition containing a) 5 to 20 wt. % of at least one isocyanate-functional polymer, b) 7 to 20 wt. % of rapeseed oil methyl ester and c) 70 to 88 wt. % of at least one filler, based on the total composition. Compositions are suitable in particular as adhesive, sealant or coating, and preferably as a parquet adhesive or joint sealing material.