Radiation-Curable Embossing Composite for Accurate Microstructure Transfer
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Solution Overview
Problem
Existing methods for transferring microstructures and nanostructures to coating surfaces often result in reduced molding accuracy, inadequate replication, and poor separation of the embossing mold, leading to loss of modulation depth and unwanted properties such as de-wetting due to mismatched surface energies.
Innovation Solution
A method using a composite of a substrate and a partially embossed, partially cured radiation-curable coating composition, comprising 1-45% crosslinkable polymer or oligomer, 40-95% reactive diluent, 0.01-15% photoinitiator, and 0-5% additive, allowing for high replication accuracy and reusable embossing without loss of modulation, even after prolonged contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional embossing mold is used to transfer microstructures to coating surface, then the embossing operation can be performed, but the molding accuracy is reduced and replication quality is inadequate
Solution Approach 1:
The patent changes the chemical composition parameters of the coating material by incorporating specific additives (silane-modified polymer, silane crosslinking agent, and surfactant) that modify surface energy and curing characteristics. This enables the coating to achieve proper adhesion and replication of microstructures without de-wetting, thereby improving molding accuracy and replication quality simultaneously.
Solution Approach 2:
The patent uses a composite coating system comprising multiple components: base polymer, silane-modified polymer, silane crosslinking agent, and surfactant. This composite formulation creates a coating that combines the benefits of adhesion promotion, controlled curing, and surface energy adjustment, resolving the contradiction between molding accuracy and replication quality.
2Duration of action of stationary object
If the embossing mold is used for prolonged contact with coating material, then more time is available for replication, but the mold integrity is compromised and separation becomes difficult
Solution Approach 1:
The patent modifies the coating composition by adding silane crosslinking agents and surfactants that control the curing kinetics and surface properties. This allows the coating to cure properly even after prolonged contact with the mold, maintaining mold integrity while enabling sufficient replication time.
Solution Approach 2:
The patent employs a disposable release liner between the mold and coating material. This thin, sacrificial layer allows prolonged contact during embossing without compromising mold integrity, as the liner is designed to be discarded after use rather than reused.
3Quantity of substance
If the coating material is applied to achieve proper coverage, then the embossed structure can be formed, but de-wetting occurs due to mismatched surface energies
Solution Approach 1:
The patent adjusts the surface energy parameters of the coating material by incorporating surfactants and silane-modified polymers. This modifies the coating's surface tension to match the mold surface energy, preventing de-wetting while maintaining proper coverage and embossed structure formation.
Solution Approach 2:
The patent introduces a release liner as an intermediary layer between the mold and coating material. This liner mediates the interaction by providing a surface that promotes coating adhesion while preventing direct bonding to the mold, thereby eliminating de-wetting issues.
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 method enables high-quality replication of microstructures and nanostructures over large areas with improved molding accuracy and separation, maintaining embossing mold integrity and reusability, independent of time elapsed since production.
Implementation Method 1
a radiation-curable coating composition, comprising (a) 1 to 45 weight % of at least one crosslinkable polymer and/or oligomer, (b) 40 to 95 weight % of at least one reactive diluent, (c) 0.01 to 15 weight % of at least one photoinitiator
Data Source
AI summary
Disclosed herein is a method for transferring an embossed structure to at least a part of a surface of a coating composition (C2a) using a composite (S1C1) including a substrate (S1) and an at least partially embossed and at least partially cured coating (C1) upon following steps (1), (2-i) and (3-i) or (2-ii) and (3-ii), and also at least step (4) and optionally step (5-i) or (5-ii), where the coating composition (C1a) is a radiation-curable coating composition of defined constitution and the composite (S1C1) is used as embossing mold (e2) of an embossing tool (E2).