Polyurethane Composite Adhesion via Temperature Control
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Solution Overview
Problem
Existing methods for producing composite components with a stable adhesive bond between thermoplastic supports and polyurethane layers lack effective control over process parameters and material compositions, leading to inconsistent adhesion properties.
Innovation Solution
A process involving a thermoplastic support with specific polycarbonate compositions and a reactive polyurethane layer, where the polyurethane raw material mixture is injected into an enlarged mould cavity to polymerize directly on the thermoplastic surface, ensuring a strong adhesive bond through controlled temperature and pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional injection moulding processes are used to produce composite components with polyurethane layers, then the basic structure can be formed, but the adhesive bond between the thermoplastic support and polyurethane layer is inconsistent and unstable
Solution Approach 1:
The patent applies parameter changes by precisely controlling the temperature of the thermoplastic support surface (maintaining it above the glass transition temperature) and the injection parameters of the polyurethane raw material mixture. This ensures optimal adhesion conditions during the coating process, resolving the inconsistency in adhesive bonding observed in conventional processes.
Solution Approach 2:
The patent implements preliminary action by pre-heating the thermoplastic support to maintain its surface temperature above the glass transition temperature before polyurethane injection. This preparatory step ensures the support surface is in the optimal state for achieving consistent and stable adhesive bonding with the polyurethane layer.
2Strength
If the polyurethane layer is applied directly on the thermoplastic support, then adhesive bonding is achieved, but control over process parameters and material composition becomes complex
Solution Approach 1:
The patent manages process control complexity by establishing specific parameter ranges: thermoplastic surface temperature above glass transition temperature, and polyurethane raw material mixture composition with 7-15 phr of processing aid. These defined parameters simplify control while ensuring strong adhesive bonding.
Solution Approach 2:
The patent introduces a processing aid substance as an intermediary component in the polyurethane raw material mixture. This processing aid (7-15 phr) facilitates adhesion between the thermoplastic support and polyurethane layer, achieving strong bonding while simplifying the overall process through a well-defined compositional parameter.
3Reliability
If specific polycarbonate compositions with high melt flowability are used, then the adhesive bonding of PU coating is improved, but the structural properties of the thermoplastic support may be compromised
Solution Approach 1:
The patent resolves this contradiction by changing the temperature parameter of the thermoplastic support to above its glass transition temperature during polyurethane injection. This temporary parameter change enables both high adhesion and structural integrity, as the support maintains its load-bearing capability while providing optimal bonding conditions.
Solution Approach 2:
The patent applies dynamics by temporarily altering the thermoplastic support's physical state (above glass transition temperature) during the coating process to enhance adhesion, then allowing it to return to its normal state for structural support. This dynamic approach enables both good coating adhesion and maintenance of support toughness.
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
This process achieves a stable and high-strength adhesive bond between the thermoplastic support and polyurethane layer, enhancing surface properties, toughness, and heat insulation, while maintaining process efficiency and reducing production time.
Implementation Method 1
a reactive polyurethane raw material mixture comprising at least one polyisocyanate component, at least one polyfunctional H-active compound, and optionally at least one polyurethane additive and/or process auxiliary substance is introduced with high pressure or low pressure machines into the gap resulting in this way between the thermoplastic component and the mould surface of the enlarged cavity, the polyurethane raw material mixture polymerizing completely in contact with the surface of the thermoplastic support to give a compact polyurethane layer
Data Source
AI summary
A composite and process for the production of a composite component, comprising a) a support of a thermoplastic composition, and b) at least one polyurethane layer in direct contact with the support.