Semi-IPN Polyurethane/Polyurea Films for Rain Erosion Resistance
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Solution Overview
Problem
Existing composite materials used in aerospace and other transportation industries face challenges in providing effective surface protection against erosion from water and particles like sand and dust, particularly in maintaining durability and adhesion during high-temperature curing processes.
Innovation Solution
A composite part with a fiber-reinforced resin matrix and an outer surface layer comprising a crosslinked polymer, such as polyurethane or polyurea, forming a semi-interpenetrating polymer network (semi-IPN) with an acrylate component, which enhances durability and resistance to erosion while allowing co-curing without pressure-sensitive adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional composite materials are used for surface protection, then manufacturing is simpler, but resistance to rain erosion and durability are insufficient
Solution Approach 1:
The patent applies composite materials by combining a crosslinked polymer (polyurethane or polyurea) with an acrylate component to form a semi-IPN structure. This composite approach provides superior rain erosion resistance and durability compared to conventional single-material coatings, while the semi-IPN architecture balances performance enhancement with manufacturing feasibility through co-curing technology.
Solution Approach 2:
The patent utilizes parameter changes by controlling the crosslinking degree and network density of the semi-IPN structure. By adjusting the crosslinking parameters and acrylate content, the material achieves optimized erosion resistance and durability while maintaining processability during curing, resolving the contradiction between enhanced performance and manufacturing complexity.
2Reliability
If pressure-sensitive adhesives are used for bonding, then ease of application is improved, but adhesion durability during high-temperature curing is compromised
Solution Approach 1:
The patent extracts and eliminates the need for pressure-sensitive adhesives by implementing a co-curing system where the outer layer and substrate are bonded through simultaneous curing of the semi-IPN structure. This removal of the adhesive layer simplifies the material system while achieving superior adhesion durability that withstands high-temperature curing processes.
Solution Approach 2:
The patent merges the bonding function and protective function into a single integrated semi-IPN structure. The crosslinked polymer network provides both structural integrity and strong adhesion to the substrate during co-curing, eliminating the need for separate adhesive layers and simplifying the manufacturing process while maintaining adhesion durability.
3Ease of manufacture
If thermoplastic polymers are used for the outer layer, then ease of processing is improved, but structural integrity during high-temperature exposure deteriorates
Solution Approach 1:
The patent applies parameter changes by transitioning from thermoplastic to thermosetting crosslinked polymers with controlled crosslinking density. This parameter change enables the material to maintain structural integrity at high temperatures while the semi-IPN structure with acrylate component ensures processability and co-curing capability, resolving the contradiction between thermal stability and ease of 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 semi-IPN composite parts demonstrate improved durability and resistance to rain erosion, maintaining structural integrity and adhesion during testing, and can be co-cured into composite structures without melting or flowing, thus offering enhanced protection and integration in industrial applications.
Implementation Method 1
an outer layer which include a semi-interpenetrating polymer network (semi-IPN)... comprising a crosslinked polymer selected from the group consisting of crosslinked polyurethane, crosslinked polyurea, and crosslinked mixed polyurethane/polyurea polymer... wherein the outer layer additionally comprises a non-crosslinked polymer forming a semi-IPN with the crosslinked polymer, wherein the crosslinked polymer may additionally comprise an acrylate-containing component
Data Source
Figure 1
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AI summary
Briefly, the present disclosure provides a film, tape or outer layer of a composite part comprising: a) at least one layer comprising a crosslinked polymer selected from the group consisting of crosslinked polyurethane, crosslinked polyurea, and crosslinked mixed polyurethane/polyurea polymer; and in some embodiments b) an adhesive layer. In some embodiments the layer additionally comprises a non-crosslinked polymer forming a semi-IPN with the crosslinked polymer. In some embodiments the non-crosslinked polymer may be selected from the group consisting of polyurethane, polyurea, and mixed polyurethane/polyurea polymer. In some embodiments the crosslinked polymer may additionally comprise an acrylate-containing component.