Web Coating Drying System for Thick Adhesive Layers
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Solution Overview
Problem
The production of thick water-based layers for pressure-sensitive adhesive tapes using existing technologies is not economically feasible due to insufficient drying capabilities, leading to residual solvent and uneven coating quality.
Innovation Solution
A method involving the application of a mass dispersed in water onto a web-shaped carrier material using a suitable applicator, followed by vacuum drying and hanging drying in a system with multiple zones, allowing for controlled drying and achieving homogeneous coatings with mass applications up to 1000 g/m².
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional drying systems with 6-12 drying zones are used for water-based coatings, then the drying capacity is sufficient for thin layers, but the system cannot achieve homogeneous drying and complete water removal for thick layers with mass application >100 g/m²
Solution Approach 1:
The drying system is segmented into multiple independent drying zones (at least 6 zones, each 1-3 meters long) with individually controllable temperatures. This segmentation allows different parts of the thick coating to be dried at different rates and temperatures, preventing uneven drying and ensuring complete water removal throughout the layer thickness.
Solution Approach 2:
Each drying zone is equipped with independent temperature control to provide locally optimized drying conditions. The temperature in each zone can be specifically adjusted according to the local drying requirements, ensuring homogeneous drying across the entire thick coating while maintaining complete water removal.
2Quantity of substance
If conventional drying systems are used for thick water-based layers, then the system structure is simple, but the drying time becomes excessively long and energy consumption increases significantly
Solution Approach 1:
The drying system employs dynamic temperature control in each drying zone, allowing the temperature profile to be adjusted and optimized during the drying process. This dynamic adjustment enables faster drying rates in later zones where the coating is thinner, significantly reducing total drying time while maintaining complete water removal for thick initial applications.
Solution Approach 2:
The drying process operates continuously through multiple zones in sequence, ensuring that the coating is constantly being dried without interruption. This continuous action through at least 6 zones maintains efficient water removal throughout the entire process, reducing overall drying time compared to intermittent or single-stage drying systems.
3Quantity of substance
If conventional drying systems are used for thick water-based layers, then the equipment complexity is low, but the energy consumption increases significantly due to insufficient drying capacity
Solution Approach 1:
The system changes the temperature parameter in each drying zone to optimize energy efficiency. By progressively adjusting temperatures across at least 6 zones, the system achieves complete water removal from thick coatings more efficiently, reducing total energy consumption compared to using a single high-temperature drying stage.
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 enables the production of thick, high-quality water-based adhesive layers with reduced solvent residue and improved coating uniformity, making it economically viable for producing pressure-sensitive adhesive tapes.
Implementation Method 1
the coated carrier material is then dried in a hanging drying system... the drying of aqueous and solvent-based coatings usually takes place in coating systems with downstream drying channels, with the help of which the solvent or water can be removed from the coating
Data Source
AI summary
Process for coating a web-shaped substrate with a mass dispersed in water, comprises applying the mass with a suitable application tool with an air permeability of at least 10 g/m 2> (dry) on the substrate and subsequently drying the coated substrate in a hang drying apparatus.