Amorphous Poly-Alpha Olefin Pellet Recrystallization Process
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Solution Overview
Problem
Amorphous poly-alpha-olefin based hot melt adhesives tend to agglomerate at elevated temperatures, making them difficult to pelletize and requiring protective packaging, whereas high crystalline adhesives are preferred for pellet formation due to their resistance to agglomeration.
Innovation Solution
A process involving extruding the adhesive through a die plate immersed in a cooling fluid, cutting it into pellets, and then recrystallizing them in a fluid at a higher temperature to create agglomeration-resistant, free-flowing pellets with increased hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If amorphous poly-alpha-olefin based hot melt adhesives are pelletized using conventional methods, then the adhesive can be processed into pellets, but the pellets tend to agglomerate at elevated temperatures
Solution Approach 1:
The patent applies parameter changes by controlling the cooling fluid temperature (T1 < 7.2°C) and recrystallization fluid temperature (T2 > T1 + 16.7°C) to transform the adhesive from a tacky state to a solidified pellet form that resists agglomeration. This temperature parameter control resolves the contradiction by enabling pelletization while maintaining agglomeration resistance through controlled crystallization.
Solution Approach 2:
The patent utilizes phase transitions by cooling the extruded adhesive in a cooling fluid to solidify it into pellets, then recrystallizing them in a warmer fluid to develop a crystalline structure that prevents agglomeration. This phase transition approach allows the adhesive to be processed into stable pellets that maintain their form at elevated temperatures.
2Reliability
If amorphous poly-alpha-olefin based hot melt adhesives are packaged in protective packaging or transported in cooled insulated rail cars to prevent agglomeration, then agglomeration is prevented, but storage and transportation complexity increases
Solution Approach 1:
The patent applies preliminary action by solidifying the adhesive into pellets and recrystallizing them to develop agglomeration resistance before storage and transportation. This pre-treatment eliminates the need for protective packaging or cooled transport, as the pellets inherently resist agglomeration at ambient conditions.
3Reliability
If high crystalline adhesives are used instead of amorphous poly-alpha-olefin based adhesives for pellet formation, then agglomeration resistance is improved, but the desired adhesive properties are compromised
Solution Approach 1:
The patent applies local quality by creating pellets with a specific crystalline structure through controlled cooling and recrystallization that provides agglomeration resistance on the surface while maintaining the amorphous poly-alpha-olefin adhesive properties in the bulk material. This allows the adhesive to exhibit both agglomeration resistance and desired adhesive performance.
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 produces pellets that remain non-blocking and free-flowing at elevated temperatures, with significantly increased hardness and faster recrystallization speed, allowing for efficient storage and transportation without agglomeration.
Implementation Method 1
extruding the adhesive through an orifice of a die plate immersed in a cooling fluid, which has a temperature T1
Implementation Method 2
solidifying the pellets in a recrystallization fluid at a temperature T2 for at least 30 minutes
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The present invention relates to a process for producing free-flowing, agglomeration resistant amorphous poly-alpha--olefin based adhesive pellets. The process includes (a) extruding the adhesive through an orifice of a die plate immersed in a cooling fluid; (b) cutting the adhesive into a plurality of pellets in the cooling fluid; (c) solidifying the pellets at a temperature range of about 25°C to about 4Q°C for at (east 30 minutes; and (6) separating the pellets from the recrystallization fluid and drying; the pellets. The pellets harden at least three folds faster than conventionally formed pellets.