Polypropylene Expanded Beads with Layered Flame Retardant
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Solution Overview
Problem
Polypropylene-based resin expanded beads with hindered amine-based flame retardants face challenges in achieving desired flame retardancy and fusion-bonding characteristics during in-mold molding.
Innovation Solution
The use of polypropylene-based resin expanded beads incorporating an NOR type hindered amine, with a surface thermoplastic polymer layer and specific blending ratios of the NOR type hindered amine, ranging from 0.03 wt% to 0.5 wt% in the beads and less than this range in the thermoplastic polymer layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hindered amine-based flame retardant is added to polypropylene-based resin expanded beads, then flame retardancy is improved, but fusion-bonding characteristics of expanded beads deteriorate
Solution Approach 1:
The patent applies local quality by creating a layered structure where the core layer contains the NOR type hindered amine flame retardant while the surface layer has reduced or zero flame retardant content. This allows the interior to provide flame retardancy while the surface maintains good fusion-bonding characteristics for in-mold molding, thus resolving the contradiction between flame retardancy and fusion-bonding characteristics.
Solution Approach 2:
The patent segments the expanded beads into distinct layers: a core layer containing the polypropylene-based resin and NOR type hindered amine flame retardant, and a surface layer with thermoplastic polymer having lower or zero flame retardant content. This segmentation allows different regions to fulfill different functions - the core provides flame retardancy while the surface enables good fusion-bonding.
2Reliability
If expansion ratio of expanded beads is increased, then flame retardancy is improved, but fusion-bonding characteristics deteriorate
Solution Approach 1:
The patent applies local quality by creating a layered structure where the core layer contains the NOR type hindered amine flame retardant while the surface layer has reduced or zero flame retardant content. This allows the interior to provide flame retardancy while the surface maintains good fusion-bonding characteristics for in-mold molding, thus resolving the contradiction between flame retardancy and fusion-bonding characteristics.
3Reliability
If in-mold molding conditions are adjusted to improve flame retardancy, then flame retardancy is improved, but fusion-bonding characteristics deteriorate
Solution Approach 1:
The patent applies local quality by creating a layered structure where the core layer contains the NOR type hindered amine flame retardant while the surface layer has reduced or zero flame retardant content. This allows the interior to provide flame retardancy while the surface maintains good fusion-bonding characteristics for in-mold molding, thus resolving the contradiction between flame retardancy and fusion-bonding characteristics.
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 results in expanded beads molded articles that exhibit excellent flame retardancy and improved fusion-bonding characteristics, maintaining the expansion ratio and in-mold molding conditions effectively.
Implementation Method 1
a covering step of covering a core layer including a polypropylene-based resin as a base material resin and an NOR type hindered amine with a thermoplastic polymer layer
Implementation Method 2
a foaming step of foaming resin beads having the core layer and the thermoplastic polymer layer obtained by the covering step to obtain the polypropylene-based resin expanded beads
Data Source
AI summary
A polypropylene-based resin expanded beads configured to include an NOR type hindered amine and has a surface on which a thermoplastic polymer layer is located, in which a blending ratio of the amine in the expanded beads is 0.03 wt % or more and 0.5 wt % or less, and a blending ratio of the amine in the thermoplastic polymer layer is less than the blending ratio of the amine in the expanded beads. Further, the method for producing the expanded beads includes a covering and foaming step, in which in the resin beads to be obtained in the covering step, a blending ratio of the amine in the resin beads is adjusted to be 0.03 wt % or more and 0.5 wt % or less, and a blending ratio of the amine in a thermoplastic polymer layer is adjusted to be lower than the blending ratio of the amine in the resin beads.