Pastillation Apparatus for Low Viscosity Polymer Solidification
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Solution Overview
Problem
Existing methods for solidifying low viscosity, low melt strength polymers are inefficient in terms of productivity and require large equipment spaces, with underwater pelletization facing challenges like blade wrap-up and 'die freeze-off', while pastillation and waterslide strand pelletization suffer from slow cooling rates and space inefficiencies.
Innovation Solution
A pastillation apparatus with a moving belt and water spray system, where the water spray ratio to discharge rate is ≥3.0 and belt residence time is ≤50 seconds, enhancing cooling efficiency and reducing space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If underwater pelletization is used to solidify low viscosity polymers, then cooling efficiency and space requirements are improved, but blade wrap-up and die freeze-off occur due to low melt strength
Solution Approach 1:
The invention divides the solidification process into discrete pastilles formed by a pastillation head with multiple orifices, rather than continuous strand cutting. Each pastille is formed individually and dropped onto the belt, eliminating blade contact with low-strength melt and preventing wrap-up issues.
Solution Approach 2:
The pastillation head forms discrete pastilles before they contact the cooling belt, pre-solidifying the outer surface. This preliminary shaping and partial solidification prevents die freeze-off by maintaining melt flowability through the orifices while ensuring clean release onto the belt.
2Adaptability or versatility
If pastillation is used to solidify low viscosity polymers, then material compatibility is improved, but productivity and cooling rate are reduced due to conductive cooling on belt
Solution Approach 1:
The invention uses hydraulic cooling by spraying water directly onto the pastilles as they travel on the belt. This liquid cooling method provides much higher heat transfer coefficients compared to conductive cooling through the belt, dramatically increasing cooling rate and productivity while maintaining compatibility with low viscosity materials.
3Adaptability or versatility
If pastillation is used to solidify polymers, then material compatibility is improved, but equipment space is increased
Solution Approach 1:
The invention merges the pastillation head, conveying belt, and water spray cooling system into a single integrated unit. The belt serves dual functions of conveying and supporting the pastilles during cooling, while water sprays are positioned to cool pastilles in-line during transport, eliminating the need for separate cooling chambers and reducing overall equipment footprint.
4Reliability
If waterslide strand pelletization is used, then solidification of low viscosity materials is improved, but throughput and space efficiency are reduced
Solution Approach 1:
The invention uses a moving belt that dynamically conveys pastilles through the cooling zone, allowing continuous high-rate production. The belt speed can be adjusted to match the cooling rate, enabling high throughput while maintaining effective solidification. Multiple pastillation heads can be arranged along the belt to increase capacity without proportionally increasing space.
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 apparatus achieves higher throughput with improved cooling efficiency and reduced space needs, effectively solidifying low viscosity polymers while preventing agglomeration and maintaining pastille quality.
Implementation Method 1
a means to transfer water onto the moving belt, such that the water comes into contact with the discrete molten polymer particles on the moving belt to form the solid polymer particles
Implementation Method 2
the water of component C is sprayed onto the discrete molten polymer particles, such that the ratio of 'the rate of water spray' to 'the discharge rate' is ≥3.0
Data Source
AI summary
An apparatus to batch or continuously form solid polymer particles, the apparatus comprising the following components: A) at least one pastillation unit comprising a pastillation head, said unit used to form discrete molten polymer particles from a polymer melt; B) a moving belt to receive and transfer the discrete molten polymer particles from the pastillation head; C) a means to transfer water onto the moving belt, such that the water comes into contact with the discrete molten polymer particles on the moving belt to form the solid polymer particles; and wherein the water of component C is sprayed onto the discrete molten polymer particles, such that the ratio of “the rate of water spray” to “the discharge rate” is ≥3.0; and wherein the belt residence time is ≤50 seconds.