Anti-misting Additive for Silicone Roll Coating
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Solution Overview
Problem
High-speed roll coating of flexible supports with liquid silicone compositions leads to misting issues, resulting in consumable loss, quality degradation, and safety concerns, with existing solutions either reducing coating quality or being complex and costly.
Innovation Solution
A process involving an anti-misting additive formed by reacting organopolysiloxanes with (meth)acrylate and amine functions, creating a branched structure that reduces misting while maintaining coating quality, involves mixing specific compounds with a molar ratio of 3.8 to 7, and is applied at temperatures between 10°C and 100°C for 30 minutes to 12 hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the linear running speed of the flexible support strip is increased to improve productivity, then coating throughput increases, but mist formation and aerosol generation increase causing consumable loss and quality degradation
Solution Approach 1:
The patent modifies the chemical composition parameters of the liquid silicone formulation by incorporating specific additives and adjusting molecular weight distribution. This changes the fluid dynamics and transfer characteristics of the coating material, reducing mist formation even at high linear speeds. The composition is tailored to maintain proper rheological properties that prevent aerosol generation during high-speed coating operations.
Solution Approach 2:
The patent creates a composite silicone composition by combining base polysiloxane materials with specific functional additives and crosslinking agents. This composite formulation achieves optimal balance between coating transfer efficiency and mist suppression, allowing high-productivity operation without the harmful aerosol effects that would occur with standard silicone formulations.
2Productivity
If the rotational speed of the coating roll is increased to improve productivity, then coating speed increases, but mist density increases causing safety concerns and fouling
Solution Approach 1:
The patent adjusts the molecular weight and viscosity parameters of the silicone composition to optimize its behavior at high rotational speeds. By controlling these physical parameters, the coating material maintains stable transfer characteristics that minimize aerosol generation even when the coating roll rotates at high speeds required for productive operation.
Solution Approach 2:
The patent introduces specific intermediary substances into the silicone composition that act as mist-suppressing agents. These intermediaries modify the surface tension and volatility characteristics of the coating material, preventing aerosol formation during high-speed rotation while still allowing effective coating transfer to the flexible support.
3Object-generated harmful factors
If the difference between tangential speed of the coating roll and linear speed of the support is increased to reduce mist, then mist density decreases, but homogeneity of the coated layer is disrupted
Solution Approach 1:
The patent optimizes the viscosity and shear thinning characteristics of the silicone composition to maintain coating homogeneity across a range of speed differentials. By adjusting these rheological parameters, the formulation compensates for speed variations between the coating roll and support, ensuring uniform coating quality while suppressing mist formation.
4Manufacturing precision
If the pressure between the coating roll and press roll is increased to improve coating transfer, then coating quality improves, but mist formation increases
Solution Approach 1:
The patent modifies the pressure-sensitivity parameters of the silicone composition by adjusting its viscosity and elastic properties. This allows the coating material to transfer effectively to the flexible support at lower roll pressures, reducing the mechanical energy input that would otherwise generate mist and aerosol during the coating process.
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 solution significantly reduces misting during high-speed coating, maintaining the quality of the crosslinked silicone coatings in terms of adhesion, release profile, and stability, while improving safety and hygiene by allowing increased coating speeds without compromising coating properties.
Implementation Method 1
crosslinkable by polyaddition
Implementation Method 2
crosslinkable by dehydrogenative condensation
Implementation Method 3
crosslinkable by polycondensation
Implementation Method 4
crosslinkable by the cationic route
Implementation Method 5
crosslinkable by the radical route
Implementation Method 6
transfer of the liquid silicone film from the coating roll onto the running flexible support strip
Data Source
AI summary
The invention relates to the general field of coating various flexible supports, such as sheets of paper or synthetic polymer (polyolefin, polyester, etc) sheets or fabric sheets, with a silicone on high-speed rolls. The invention relates to an efficient method for preventing mist formation when coating flexible supports with a liquid silicone composition precursor of cross-linked coatings, said coating process being performed using a coating device that includes a roll operating at a high speed.