Curable Composition Using Segmented Crosslinking for Complete Hardening
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Solution Overview
Problem
Conventional photocurable compositions fail to fully harden areas that are not exposed to light, leading to issues like dirt and unhardened composition bleeding, while also lacking in mechanical physical properties, heat resistance, and weather resistance.
Innovation Solution
A curable composition comprising a vinyl polymer with at least one crosslinkable silyl group and a vinyl polymer with a photo-crosslinkable group, along with a photopolymerization initiator, which allows for rapid curing and improved mechanical, heat, and weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vinyl polymer with photo-crosslinkable groups is used for rapid curing, then curability speed is improved, but areas not exposed to light remain unhardened causing dirt and bleeding
Solution Approach 1:
The patent divides the crosslinking mechanism into two independent segments: a photo-crosslinkable segment (vinyl polymer with acryloyl/methacryloyl groups) for rapid initial curing where light is applied, and a moisture-crosslinkable segment (silyl groups) for complete hardening in all areas including those not exposed to light. This segmentation allows each mechanism to fulfill its specific function without compromising the other.
Solution Approach 2:
The photo-crosslinking reaction acts as a preliminary action that rapidly forms an initial crosslinked structure in light-exposed areas, providing immediate curing performance. Subsequently, the moisture-crosslinking reaction completes the hardening process in all areas, ensuring complete coverage including shadowed regions. This preliminary action sequence resolves the contradiction between speed and completeness.
2Reliability
If polysiloxane-based polymers with silyl groups are used for weather resistance, then weather resistance is improved, but staining and painting performance deteriorate
Solution Approach 1:
The patent creates a composite material system combining vinyl polymer chains with grafted silyl crosslinking groups. This composite structure integrates the beneficial weather resistance of siloxane crosslinks while maintaining the superior painting performance and stain resistance of vinyl polymer matrices, eliminating the harmful staining effects of conventional polysiloxane systems.
3Reliability
If polyisobutylene is used for weather resistance and moisture resistance, then these properties are improved, but viscosity increases making handling difficult
Solution Approach 1:
The patent changes the chemical structure parameters by using vinyl polymer backbones with grafted silyl groups instead of polyisobutylene chains. This parameter change maintains the desired weather and moisture resistance through siloxane crosslinking while significantly reducing viscosity and improving handling characteristics compared to polyisobutylene-based systems.
4Strength
If hydrocarbon polymers with internal double bonds are used for flexibility, then flexibility is improved, but heat resistance and weather resistance deteriorate
Solution Approach 1:
The patent extracts the harmful internal double bonds from the polymer main chain by using vinyl polymer backbones without unsaturation. The desired flexibility is maintained through the vinyl polymer structure itself, while heat and weather resistance are improved by eliminating the vulnerable internal double bonds that would otherwise degrade under thermal and environmental stress.
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 composition ensures complete hardening where light is applied, while maintaining rapid curability and achieving superior mechanical physical properties, heat resistance, and weather resistance.
Implementation Method 1
a photopolymerization initiator (III)
Data Source
AI summary
Disclosed is a curable composition which can be cured quickly by light. This curable composition is not left uncured even in portions which are not irradiated with light. A cured product of this curable composition is excellent in heat resistance, oil resistance and weather resistance. Specifically disclosed is a curable composition characterized by containing a vinyl polymer having at least one crosslinkable silyl group on average and a vinyl polymer having at least one photocrosslinkable group on average.