Coating Polymer Particles with Cold Walls to Prevent Fouling
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Solution Overview
Problem
Existing coating processes for polymer particles result in fouling of equipment due to deposition of the composition on walls, requiring frequent cleaning, especially when processing different additives consecutively.
Innovation Solution
Maintaining polymer particles in motion during coating with a composition of additive and binder, and operating the coating process in a container with walls at a temperature below the binder's film-forming temperature, preventing binder film formation on walls and ensuring that any deposits are easily removed by the moving particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the composition is sprayed onto polymer particles in a coating process, then the polymer particles can be coated with the additive-containing binder, but the composition deposits on the walls of the equipment and causes fouling that requires frequent cleaning
Solution Approach 1:
The patent applies parameter changes by controlling the temperature of the walls to be below the film-forming temperature of the binder. This temperature parameter modification prevents the binder from forming adherent films on the walls, causing any deposited composition to remain non-stick and be readily removed by the moving polymer particles, thereby reducing fouling and cleaning requirements
Solution Approach 2:
The patent converts the harmful effect of composition deposition on walls into a beneficial effect by utilizing the temperature differential. The deposited composition, instead of forming adherent fouling, condenses on the cold walls as non-stick material that is automatically cleaned by the moving particles, turning the fouling problem into a self-cleaning mechanism
2Reliability
If cleaning is performed after each additive change to prevent fouling, then equipment cleanliness is maintained, but production time is lost due to frequent cleaning interruptions
Solution Approach 1:
The patent applies preliminary action by pre-cooling the walls before the coating process begins. This preliminary temperature preparation ensures that when the composition is sprayed, the walls are already at the correct temperature to prevent adherent film formation, eliminating the need for intermediate cleaning operations between batches
Solution Approach 2:
The patent enables continuity of useful action by allowing multiple batches to be processed with the same additive without intermediate cleaning. The controlled wall temperature maintains continuous coating operation, and when additive changes are needed, the process can continue uninterrupted because the non-stick deposits do not compromise equipment cleanliness
3Manufacturing precision
If the binder is applied at a temperature above its film-forming temperature to ensure proper coating formation, then the additive-containing layer forms correctly on the particles, but the binder forms films on the walls causing fouling
Solution Approach 1:
The patent applies local quality by creating different thermal environments in different locations. The polymer particles are maintained at a temperature above the binder's film-forming temperature to ensure proper coating formation, while the walls are maintained at a temperature below the film-forming temperature to prevent adherent film formation. This spatial differentiation of temperature conditions allows both objectives to be achieved simultaneously
Solution Approach 2:
The patent segments the thermal control into two distinct zones: the particle phase and the wall phase. The particles experience one temperature regime that promotes binder film formation, while the walls experience a different temperature regime that prevents fouling. This segmentation of thermal conditions resolves the contradiction between proper coating formation and wall cleanliness
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 approach significantly reduces fouling of the coating space, allowing multiple batches to be coated with the same additive without intermediate cleaning, even when switching additives, resulting in a more predictable and reproducible coating process with uniform distribution of the additive-containing binder layer.
Implementation Method 1
a certain degree of condensation of the distributing agent on the colder wall surface will take place so that drying in of the composition on the wall is prevented
Implementation Method 2
at a temperature at which the binder can form a film
Data Source
AI summary
Process for the coating of objects, comprising contacting the objects with a composition comprising an additive, a film-forming binder and optionally a distributing agent, at a temperature below the softening temperature Tp of the objects and at a temperature at which the binder can form a film, forming and consolidating an additive-containing layer of binder on the surface of the objects, the objects being kept in mutual motion while they are being contacted with the composition and while the additive-containing layer of binder is being formed and consolidated, which process is carried out in a container bounded by walls of which the temperature of the walls is so much lower than the application temperature that formation of a film of the binder on the walls is prevented.