Ballistic-Resistant Composite With Blocked Isocyanate Cross-Linking
Solution Overview
Problem
Existing ballistic-resistant composites face challenges in achieving a balance between formability and performance, as thermoplastic resins lack chemical bonding during lamination, while thermoset resins become inflexible after curing, limiting their adaptability and ballistic efficiency.
Innovation Solution
Incorporation of a blocked isocyanate into the resin matrix, which is cross-linkable by heating to a specific temperature, allowing for chemical bonding between layers and enhancing the sonic modulus of the composite, thereby improving ballistic resistance and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If thermoplastic resins are used in the resin matrix, then formability and flexibility are improved, but inter-laminar bond strength and ballistic performance deteriorate due to lack of chemical bonding
Solution Approach 1:
The patent changes the chemical state of isocyanate from blocked (inactive) to unblocked (reactive) by controlling temperature parameters. During lamination, the isocyanate remains blocked to maintain formability, then during curing, heating activates the isocyanate to form chemical bonds, achieving both formability and strength
Solution Approach 2:
The blocked isocyanate acts as an intermediary substance that enables controlled chemical bonding. It remains dormant during processing (allowing formability) then activates to create cross-links (providing bond strength), mediating between the conflicting requirements of flexibility and strength
2Strength
If thermoset resins are used in the resin matrix, then inter-laminar bond strength is improved through chemical bonding, but formability and flexibility deteriorate due to inflexibility after curing
Solution Approach 1:
The patent applies preliminary action by pre-blocking the isocyanate groups before lamination. This prevents premature chemical bonding during the formability stage, allowing layers to be stacked and shaped freely, then enables bonding only when desired during the curing stage
Solution Approach 2:
The resin matrix transitions from a dynamic, flexible state during lamination to a rigid, bonded state during curing. The blocked isocyanate enables this dynamic transformation, allowing the material to adapt to processing requirements then lock into its final structure
3Strength
If blocked isocyanate is added to the resin matrix, then inter-laminar bond strength and ballistic performance are improved, but resin matrix complexity and processing difficulty increase
Solution Approach 1:
The blocked isocyanate system is self-service in that it automatically activates at the appropriate temperature during curing without requiring external catalysts or complex processing interventions. The resin itself provides the mechanism for bonding, reducing the need for additional processing equipment or steps
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 use of blocked isocyanate in the resin matrix enables improved inter-laminar tensile bond strength, increased bending stiffness, and reduced back-face deformation, leading to enhanced ballistic performance and formability of composite armor.
Implementation Method 1
The resin matrix is cross-linkable by heating to a temperature that causes the isocyanate to liberate from the blocking agent and the liberated isocyanate to reactively cause cross-linking of the resin matrix
Implementation Method 2
the liberated isocyanate to reactively cause cross-linking of the resin matrix
Data Source
Figure 1A~1B
Figure 2
Figure 3~5
AI summary
A ballistic-resistant composite includes at least one layer that has a network of ballistic fibers and a resin matrix. The resin matrix includes blocked isocyanate that is composed of isocyanate bonded with a blocking agent. The resin matrix is cross-linkable by heating to a temperature that causes the isocyanate to liberate from the blocking agent and the liberated isocyanate to reactively cause cross-linking of the resin matrix.