Silane-Functional Polyester Adhesives for Initial Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing moisture-curing compositions, such as adhesives and coatings based on silane-terminated polymers, often have low initial strength, which requires substrates to be fixed until sufficient strength is achieved, and warm or hot melt adhesives face challenges with viscosity increase and lack of elasticity for thermal expansion compensation.
Innovation Solution
The use of specific silane-functional polyesters with a crystalline, hydroxyl group-terminated polyester structure, which reacts with isocyanatosilanes to form a reactive melt component, providing improved initial strength and mechanical properties by crystallizing quickly after application, allowing for faster achievement of sufficient adhesive strength and maintaining deformability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If moisture-curing compositions use conventional reactive components, then the composition can be stored and applied, but the initial strength is low requiring substrate fixation
Solution Approach 1:
The patent changes the molecular weight parameter of the polyester polyol to a specific range (2500-7000 g/mol) and controls the silane content (0.1-5 mmol/g) to achieve optimal initial strength. These parameter optimizations enable the adhesive to reach sufficient strength without requiring substrate fixation, directly resolving the contradiction between initial strength and fixation time.
Solution Approach 2:
The invention creates a composite system by combining silane-functional polyester with specific molecular weight characteristics and controlled silane content. This composite material structure provides both adequate initial strength for immediate handling and maintains the moisture-curing mechanism for final bond strength, eliminating the need for fixation time.
2Strength
If warm or hot melt adhesives are used to achieve high initial strength, then the adhesive sets quickly, but the viscosity increases sharply making corrections difficult
Solution Approach 1:
The patent optimizes the polyester polyol molecular weight (2500-7000 g/mol) and silane content parameters to achieve a balance between initial strength development and operational flexibility. This parameter control allows the adhesive to maintain workable viscosity while developing sufficient initial strength, enabling alignment corrections without the sharp viscosity increase characteristic of conventional hot melts.
3Strength
If warm or hot melt adhesives are used for quick setting, then initial strength is improved, but elasticity is insufficient for thermal expansion compensation
Solution Approach 1:
The invention creates a composite adhesive system that combines the rapid initial strength characteristics of warm/hot melt adhesives with the elasticity needed for thermal expansion compensation. The specific polyester polyol molecular weight range and silane functionalization create a material that exhibits both quick setting and adequate elasticity, resolving the contradiction between initial strength and adaptability.
4Strength
If high molecular weight polyesters are used, then mechanical properties improve, but the adhesive remains too viscous for proper application
Solution Approach 1:
The patent precisely controls the polyester polyol molecular weight within the range of 2500-7000 g/mol, which is high enough to provide good mechanical properties but low enough to maintain acceptable viscosity for application. This parameter optimization resolves the contradiction between mechanical strength and applicability by finding the optimal molecular weight window.
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 silane-functional polyesters enhance the initial strength and mechanical properties of moisture-curing compositions, enabling shorter fixation times for bonded substrates and improved elasticity, particularly beneficial for applications like vehicle windshields.
Implementation Method 1
providing improved initial strength and mechanical properties by crystallizing quickly after application
Implementation Method 2
Within a silane group in the polyester of the formula (I), R1 may independently be an alkyl group with 1 to 3 carbon atoms
Implementation Method 3
moisture-curing compositions based on silane-functional polymers
Data Source
AI summary
The present invention relates to silane-functional polyesters obtainable from the reaction of a room temperature solid polyester with an isocyanatosilane, which are used as a constituent in moisture-curing compositions such as adhesives, sealants or coatings based on silane-terminated polymers. By virtue of the use of inventive silane-functional polyesters, it is possible in particular to provide adhesives with a high initial strength.