Polyether Block Copolymers for Solvent-Free Adhesives
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Solution Overview
Problem
Existing polyurethane-based hot-melt adhesives and sealants face challenges with phase and domain separation, limiting their miscibility and adhesion properties across various substrates, and often require solvents, which complicates processing and reduces their effectiveness.
Innovation Solution
The development of polyether block copolymers with a central block of polyacrylate or polymethacrylate units and polyoxypropylene blocks, prepared using double metal cyanide catalysts, which enhances miscibility and prevents separation, allowing for the creation of solvent-free, high-strength adhesives and sealants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyurethane prepolymers are used as hot-melt adhesives, then adhesion performance is improved, but phase separation occurs limiting miscibility
Solution Approach 1:
The patent employs block copolymers with distinct polyether blocks and polyester blocks as composite materials. The polyether blocks provide adhesion performance while the polyester blocks provide compatibility with the polyurethane prepolymer, preventing phase separation and ensuring miscibility throughout the adhesive composition.
Solution Approach 2:
The patent modifies the chemical structure parameters of the adhesive components by using specific block copolymers with controlled molecular weights and compositions. This changes the compatibility parameters between components, allowing them to mix homogeneously while maintaining adhesion performance.
2Device complexity
If solvent-free compositions are used, then processing complexity is reduced, but adhesion performance may be compromised
Solution Approach 1:
The patent changes the physical state parameters of the adhesive components by using block copolymers with carefully selected molecular weights and compositions that remain liquid or semi-liquid at room temperature. This eliminates the need for solvents while maintaining processability and adhesion performance.
3Stability of the object's composition
If polyether block copolymers with polyoxypropylene blocks are used, then miscibility is improved, but adhesion to certain substrates may be reduced
Solution Approach 1:
The patent creates a composite structure where polyether blocks provide miscibility and flexibility, while polyester blocks and polyurethane segments provide polar interactions and adhesion to substrates. This composite approach ensures both miscibility within the adhesive and adhesion to various substrates.
Solution Approach 2:
The patent applies local quality by having different blocks of the copolymer perform different functions: polyether blocks for miscibility and flexibility in the bulk adhesive, and polyester/polyurethane blocks for adhesion at the substrate interface. Each region of the molecule is optimized for its specific role.
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 polyether block copolymers ensure excellent miscibility and adhesion to multiple substrates, preventing phase separation and resulting in high-strength, solvent-free adhesives and sealants with improved processing characteristics.
Implementation Method 1
prepared using double metal cyanide catalysts
Data Source
AI summary
The invention relates to polyether block copolymers of the general structure B-(A-OH)n. N is equal to or greater than 2 and the blocks A consist of polyoxypropylene units and the central block B consists of polyoxytetramethylene, polyoxyethylene, polybutadiene, polyisoprene, polyacrylate, polymethacrylate, polyamide, polyurethane, or polyester units. Said polyether block copolymers are suitable for producing compositions serving as the basis for preparations for use as single-component moisture-curing or two-component adhesive or sealing agents, for assembly adhesion, for surface adhesion and/or coating, as a reactive melt adhesive, or as a laminating adhesive.