Fluidized Bed Dip Coating for Solvent-Free Biodegradable Gloves
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Solution Overview
Problem
Existing dip forming processes for articles like surgical gloves are not environmentally friendly due to solvent evaporation and high energy usage, and biodegradable polymers like PLA are difficult to process into small particles for glove manufacturing.
Innovation Solution
A fluidized bed dip forming process using cryogrinding to create particles below 500 micrometers, suspending them in air to form a fluid-like suspension, and applying a plasticizer layer followed by a PLA powder layer, then fusing at a controlled temperature to create biodegradable, renewable gloves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dip forming process with solvent evaporation is used, then articles can be produced with adequate mechanical properties, but environmental pollution and high energy consumption occur
Solution Approach 1:
The patent extracts and eliminates the harmful solvent evaporation step from the conventional dip forming process. By using a fluidized bed of polymer particles instead of a polymer solution, the process removes the need for solvent evaporation, thereby eliminating volatile organic compound emissions and associated environmental pollution while maintaining article production quality
Solution Approach 2:
The patent changes the physical state and processing parameters of the polymer material. Instead of using polymer solutions that require solvent evaporation, the process uses polymer particles in a fluidized bed state, allowing deposition through controlled fluidization and subsequent fusion, fundamentally altering the processing mechanism to eliminate harmful emissions
2Ease of manufacture
If PLA pellets are ground to small particles for dip forming, then processability improves, but energy consumption increases significantly
Solution Approach 1:
The patent performs cryogrinding of PLA pellets to create small particles beforehand, before the dip forming process. This preliminary particle size reduction enables subsequent fluidization and coating operations to proceed efficiently without requiring excessive energy during the actual manufacturing process, as the particles are already sized appropriately for fluidized bed processing
3Ease of operation
If solvent or water is used in dip forming process, then polymer coating can be applied easily, but high energy is required for solvent removal
Solution Approach 1:
The patent extracts and eliminates the solvent or water component from the dip forming process. By using a fluidized bed of dry polymer particles instead of polymer solutions or dispersions, the process removes the need for thermal evaporation of solvents, thereby eliminating the high energy requirement for solvent removal while maintaining coating application capability
Solution Approach 2:
The patent replaces the thermal evaporation mechanism (heating to remove solvent) with a mechanical fluidization and deposition mechanism. Polymer particles are fluidized by air flow and deposited onto the substrate, followed by fusion through controlled heating, substituting the solvent-mediated process with a direct particle deposition approach that eliminates energy-intensive solvent evaporation
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 process eliminates solvent use, reduces energy consumption, and produces pinhole-free, biodegradable gloves using renewable materials, addressing environmental concerns and manufacturing challenges.
Implementation Method 1
suspending them in air to form a fluid-like suspension
Implementation Method 2
A powder layer of PLA is coated over the plasticizer layer using a fluidized bed PLA powder dip forming process. The process involves cryogrinding the PLA pellets to particles having a size below about 500 micrometers
Implementation Method 3
The dip formed article can then be released from the mold after cooling
Data Source
AI summary
The present disclosure relates to plasticized polymer compositions and a process for forming plasticized polymers. The process involves first coating the substrate with a plasticizer containing layer by dip coating. A powder layer of polymer is coated over it using a fluidized bed of polymer powder by dip forming process. The process involves cryogrinding the polymer pellets to below about 500 micrometer size particles, preferably below about 100 micrometer size particles, fluidizing the particles with or without fluidizing additives, by suspending the particles in air, by flowing air in a controlled manner upwards in a column resulting in an air solid suspension. The process can be used to make dip formed articles and dip coated substrates. This environmentally friendly process can be applied to bioplastics to make ecofriendly articles.