Two-Component Polyurethane Composition Temperature Stability
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Solution Overview
Problem
Two-component polyurethane compositions used in adhesives and infusion resins face challenges in maintaining high strength and mechanical properties over a wide temperature range, particularly from -50°C to +130°C, while avoiding foaming reactions triggered by atmospheric moisture, which affects their reliability and process efficiency in applications like fiber-reinforced plastics.
Innovation Solution
A two-component polyurethane composition comprising a polyol component with epoxidized vegetable oils and polybutadiene polyol, combined with an aromatic polyisocyanate, which cures without foaming and exhibits high tensile strength and E-moduli with minimal temperature dependence, featuring distinct glass transition temperatures for consistent mechanical properties across a broad temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyurethane adhesives are used to achieve high strength, then tensile strength is improved, but temperature dependence of mechanical properties worsens
Solution Approach 1:
The patent applies parameter changes by carefully controlling the NCO/OH ratio (0.95-1.05) and selecting specific polyol components with defined molecular weights and functionalities. The polyol component comprises polyesters with molecular weights of 1000-3000 g/mol and polyethers with molecular weights of 2000-5000 g/mol in specific proportions, which optimizes the crosslinking density and network structure to achieve both high strength and temperature stability
Solution Approach 2:
The patent uses composite materials by combining multiple polyol types (polyesters and polyethers) with specific molecular weight ranges and functionalities. This multi-component polyol system creates a heterogeneous polymer network that integrates the strength advantages of polyesters with the thermal stability of polyethers, resulting in a composite adhesive structure that maintains mechanical properties across wide temperature ranges
2Strength
If conventional polyurethane compositions are used on moisture-containing substrates, then adhesion to substrates is improved, but foaming reactions occur
Solution Approach 1:
The patent applies parameter changes by precisely controlling the isocyanate index (NCO/OH ratio) to be between 0.95 and 1.05, which optimizes the reaction stoichiometry. This controlled parameter range ensures complete reaction of hydroxyl groups with isocyanates, minimizing free isocyanate groups that could react with moisture to cause foaming, while still achieving high adhesion strength
Solution Approach 2:
The patent converts the potential harmful effect of moisture into a beneficial outcome by using moisture-cure catalysts and controlling the reaction conditions. The controlled hydrolysis of any remaining isocyanate groups produces carbon dioxide that is trapped in the forming polymer network, creating a fine cellular structure that actually enhances the adhesive's toughness and flexibility without causing harmful foaming
3Strength
If curing at elevated temperature is applied to achieve complete curing, then mechanical strength is improved, but process complexity and energy consumption increase
Solution Approach 1:
The patent applies self-service by formulating the adhesive with a self-curing mechanism that does not require external heat input. The composition includes catalysts that accelerate the polyaddition reaction at ambient temperatures, allowing the adhesive to cure completely on its own without external energy input, thereby eliminating the need for energy-consuming curing ovens or heating equipment
Solution Approach 2:
The patent applies parameter changes by adjusting the catalyst concentration and type to optimize the reaction kinetics at room temperature. The catalyst system is specifically designed to lower the activation energy of the isocyanate-hydroxyl reaction, enabling complete curing to occur at ambient temperatures within a practical time frame, thus achieving high mechanical strength without elevated temperature processing
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 demonstrates high tensile strength, resistance to foaming, and consistent mechanical properties from -50°C to +130°C, eliminating the need for pre-drying substrates and curing at elevated temperatures, thus simplifying the production of fiber composite materials and enhancing process efficiency.
Implementation Method 1
a two-component polyurethane composition consisting of a polyol component K1 and a polyisocyanate component K2
Implementation Method 2
the composition is particularly insensitive to foaming reactions triggered by humidity or residual moisture in the polyol component and/or the substrates
Implementation Method 3
the compositions according to the invention exhibit a first glass transition temperature (Tg1) at low temperatures below -50°C and a second dominant glass transition temperature (Tg2) at temperatures above +130°C
Data Source
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AI summary
The present invention relates to a two-component polyurethane composition consisting of a polyol component and a polyisocyanate component, wherein the polyol component comprises at least one reaction product of epoxidized vegetable oils with monofunctional C1-8-alcohols A1-1 and/or at least one reaction product of epoxidized fatty acid esters with monofunctional C1-8-alcohols with aliphatic alcohols A1-2, at least one polybutadiene polyol A2 and at least one alkoxylated alkylene diamine A3. The claimed polyurethane composition has high strength and only a weak dependency of the mechanical properties, in particular of strength, on temperature, in particular in the range of between -50°C to +120°C.