Segmented Block Copolymer Reactive Extrusion TPU Compatibility
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Solution Overview
Problem
Current methods for blending thermoplastic polyurethane (TPU) and styrene block copolymers (SBCs) result in non-homogeneous mixtures with poor mechanical properties due to incompatibility, thermal degradation, and high production costs, limiting their applications due to poor hydrolytic and weather resistance.
Innovation Solution
A segmented block copolymer composition based on diblock and triblock copolymers of vinyl aromatic monomers and hydrogenated butadiene blocks linearly bonded by N or O atoms, obtained through reactive extrusion, which enhances compatibility and mechanical properties when incorporated into TPU and SBCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If mechanical blending or co-extrusion is used to blend TPU and SBC, then mixing intimacy is improved, but thermal degradation occurs and mechanical properties deteriorate
Solution Approach 1:
The patent uses a compatibilizer (block copolymer with reactive end groups) as an intermediary substance to facilitate bonding between TPU and SBC phases. This compatibilizer contains functional groups that react with both TPU and SBC, creating a bridge between the incompatible phases and preventing thermal degradation during processing
Solution Approach 2:
The patent changes the chemical parameters of the blend system by introducing reactive functional groups (isocyanate, hydroxyl, or carboxyl groups) that enable chemical bonding between phases. This transforms the physical blending process into a chemical reaction process, occurring at lower temperatures that prevent thermal degradation
2Stability of the object's composition
If compatibilizing agents with maleic groups are used, then compatibility between TPU and SBC is improved, but crosslinking reactions occur that increase viscosity and reduce processability
Solution Approach 1:
The patent applies local quality by placing reactive functional groups specifically at the end blocks of the compatibilizer chains, rather than throughout the entire polymer chain. This localized reactivity enables controlled interfacial bonding without extensive crosslinking, maintaining bulk polymer processability while achieving phase compatibility
3Strength
If TPU and SBC are blended, then mechanical properties are improved, but hydrolytic and weather resistance deteriorate
Solution Approach 1:
The patent creates a composite material system where TPU and SBC phases are chemically bonded through compatibilizer bridges. This composite structure combines the mechanical advantages of both polymers while the chemical bonding network prevents phase separation and water penetration, maintaining hydrolytic and weather resistance despite the blend composition
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 segmented block copolymer composition improves tensile strength, tear resistance, abrasion resistance, and adhesion properties, allowing for the creation of high-performance thermoplastic compositions and polyurethane foams with enhanced mechanical and adhesive properties without the need for additional adhesives.
Implementation Method 1
the most common process is a reactive extrusion, wherein a polyol containing poly-hydroxyl compounds, chain extenders, additives, and isocyanate compounds are fed into an extruder in a precise ratio aiming to achieve the properties needed for the final application
Implementation Method 2
TPU is the reaction product of a diisocyanate, a chain extender (a short chain diol) and a polyol, wherein urethane groups are formed along the polymer chain
Data Source
AI summary
The present invention relates to a segmented block copolymer composition based on diblock and/or triblock copolymers of vinyl aromatic monomer and hydrogenated butadiene blocks and thermoplastic polyurethane blocks which are linearly bonded by N or O atoms, and its procedure of obtainment based on reactive extrusion. Furthermore, the present invention relates to a thermoplastic composition, a laminate structure and a polyurethane foam, with improved properties, comprising the segmented block copolymer composition.