Relief Roller Gap Forming for Adhesive Microstructures
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Solution Overview
Problem
Current methods for producing nano- and microstructured surfaces in self-adhesive layers are limited by their complexity, scalability, and suitability for high, complex structures, often requiring high mechanical effort and being unsuitable for sensitive supports, with existing processes being time-consuming and prone to tool wear.
Innovation Solution
A method involving a relief roller with a surface relief that guides a self-adhesive polymer mixture through a gap formed by the relief and nip rollers, where the rollers rotate in opposite directions, allowing the polymer mixture to be shaped without direct contact with the relief, enabling the creation of structures of varying dimensions on sensitive carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If stamp embossing is used to create microstructures in self-adhesive layers, then complex structures such as lenses and prisms can be replicated with high impression quality, but the process becomes very time-consuming and causes high wear and tear on the tool
Solution Approach 1:
The patent replaces the mechanical stamp embossing process with a flow-based forming process. The adhesive mixture is guided through a gap between rollers where the structure is formed by flow dynamics rather than mechanical pressure, eliminating tool wear and enabling continuous production while maintaining structural complexity
Solution Approach 2:
The patent uses a flow-based system where the adhesive mixture flows through a controlled gap between rollers. The flow dynamics and pressure distribution within the gap enable structure formation without direct mechanical contact, replacing the stamping mechanism with a fluid dynamics-based approach
2Manufacturing precision
If structured rollers are used to press structures into adhesive, then microstructures can be created, but the adhesive contaminates the tool and deforms it when removed
Solution Approach 1:
The patent introduces a gap between the rollers as an intermediary space where structure formation occurs without direct contact. The adhesive flows through this gap and is shaped by the pressure distribution and flow dynamics, preventing contamination of the roller surfaces while maintaining structure formation capability
Solution Approach 2:
The patent extracts the adhesive from direct contact with the structured surface by forming structures within the gap flow. The structure is created in the adhesive itself during flow through the gap, rather than being pressed from an external tool, eliminating the contamination problem
3Productivity
If rotary embossing is used to achieve very high process speeds, then quasi-seamless structuring is obtained, but the process requires mechanically and thermally very stable polymers and high mechanical effort
Solution Approach 1:
The patent replaces the high-mechanical-effort rotary embossing system with a flow-based gap forming process. The structure is created by guiding the adhesive through a controlled gap where flow dynamics and pressure distribution form the structure, eliminating the need for high mechanical pressures and complex roller mechanisms
Solution Approach 2:
The patent changes the fundamental process parameter from mechanical pressure (in embossing) to flow rate and gap geometry. This allows processing of less stable polymers that cannot withstand high mechanical and thermal loads, while maintaining high production speeds through continuous flow
4Manufacturing precision
If injection molding is used to produce microstructured polymers, then small areas can be created with precise structures, but the process is limited to small production areas
Solution Approach 1:
The patent implements a continuous flow process where adhesive is continuously guided through the gap between rollers, enabling seamless structure formation across large areas. The continuous action eliminates the area limitations of injection molding by maintaining uninterrupted production across the entire roller width
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 method allows for rapid, seamless production of high, complex nano- and microstructures on self-adhesive layers with reduced mechanical effort, enabling the use of sensitive supports and achieving excellent structure transfer without tool contamination or deformation.
Implementation Method 1
an adhesive, in particular self-adhesive, polymer mixture is guided into a gap which is formed by a relief roller, the surface of which is provided with a relief which represents the negative of the surface structure to be produced on the adhesive layer, and is formed by a nip roller
Data Source
AI summary
The process for producing nanostructured and/or microstructured surfaces in a self-adhesive layer, comprises guiding an adhesive polymer mixture into a nip formed by a relief roll (10) and a nip roll (20), and blending the polymer mixture with colorants and/or fillers. A surface of the relief roll is provided with a relief (11), which represents the negative of the surface structure to be produced on the adhesive layer. The relief roll and the nip roll rotate in opposite directions. The nip roll wrapped partly around the relief roll is a web-form carrier material (40). The process for producing nanostructured and/or microstructured surfaces in a self-adhesive layer, comprises guiding an adhesive polymer mixture into a nip formed by a relief roll (10) and a nip roll (20), and blending the polymer mixture with colorants and/or fillers. A surface of the relief roll is provided with a relief (11), which represents the negative of the surface structure to be produced on the adhesive layer. The relief roll and the nip roll rotate in opposite directions. The nip roll wrapped partly around the relief roll is a web-form carrier material (40), which is guided through the nip and whose speed corresponds to the peripheral speed of the relief roll. The adhesive polymer mixture is pressed through the nip so that the near-roll surface of the polymer mixture is shaped in accordance with the relief, lies in layer form on the carrier material after passage through the nip, and is guided away with the carrier material. A feed roll forms a further nip with the nip roll. The feed roll and the nip roll rotate with the same peripheral speed. The polymer mixture is first applied to the feed roll, is guided into the further nip, and is guided into the nip between the relief roll and the nip roll while the remaining on the nip roll after passing through the nip. The rolls are heated to a temperature above the melting point of the used polymer mixture or cooled. The relief is produced by sandblasting, etching, laser ablation, lithographic techniques, offset printing, electroplating techniques, lithography-galvanic, cutting, milling and/or erosion, or the relief roll is composed of a roll with a form tool wrapped around it. The structure depth of the counter-relief produced in the self-adhesive layer is 1-3000 mu m, and the structure width is 0.5 mu m to 10 cm. The peripheral speed of the nip roll is more than 70% of the peripheral relief roll. The relief roll and the nip roll rotate with the same peripheral speed. After passage through the nip, the self-adhesive layer is taken from the carrier material and transferred to a second carrier. The carrier material is an inherently impervious strip. The polymer mixture at processing temperature is in softened or melted form. The self-adhesive composition is filled with microballoons. After structuring, the polymer (31) is subjected to cross-link by ionizing radiation. An independent claim is included for a self-adhesive coating obtained in a process.