Hello and welcome to another material selection example using the Polymer Selection Funnel method (POMS-Funnel-Method; in detail explained here and in this video). Aim is to select the optimal polymer material for a panhandle which most of us are familiar with and have in our kitchen.
Figure 1 presents the four different stages of the material selection funnel and this overview serves us as a guideline.
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| Figure 1: Polymer Selection Funnel - overview of the four different funnel stages . |
Polymer material selection for a kitchen panhandle
This panhandle is used in professional environments as well as in everyday life kitchens (Figure 2). It needs to cover a range of requirements which we understand better by following our polymer material checklist which consists of 12 sections and can be downloaded here.
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| Figure 2: Overview of a pan with the handle. Aim is to select the optimal polymer for this handle. |
Funnel stage 1: Material selection factors
In the first Funnel stage we focus on gathering and understanding all the requirements of the panhandle
For this product, the minimum requirements according customer specification are:
-Continuous operating temperature (long-term heat resistance): 130°C
-Short term heat resistance: HDT-A between 290°C and 320°C
-UL94 fire rating: HB at all thickness levels
-Good stiffness level at elevated temperature: min 5 GPA storage modulus at 100°C
-Food contact approved including EU 2011-10 and FDA
-Dishwasher use proof
-Good surface appearance (black color)
-Economical: handle must be produced using water coolable moulds with high productivity
-Product Carbon Footprint: < 7 kg CO2/kg
-Easy cleaning an low sticking properties
-Good impact performance in case of dropping the pan
Furthermore, in Table 1 we summarized all important requirement information (requirement worksheet).
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Table 1: Requirement worksheet for the panhandle.
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Funnel stage 2: Decision on thermoplastic or thermoset
Reflecting on the must-have requirements which need to be fulfilled, thermoplastics present the optimal choice. Thermosets will struggle with the food contact regulations, together with the mechanical properties, in particular the impact performance, since they are hard and quite brittle. However, There are Bulk Moulding Compounds (BMCs) such as the BMC 1000 from LyondellBasell Industries which use Unsaturated Polyester as base polymer, have food contact approval and may be a suitable grade for this application.
Amorphous polymers are transparent and have good temperature and mechanical performance. They are prone to stress cracking, have a lower chemical resistance (dishwasher cleaning agents) and their fatigue performance is lower compared to semi-crystalline polymers too. On the other hand, semi-crystalline engineering polymers have good high heat performance, together with good chemical resistance and mechanical properties.
After this analysis we can make a preselection of suitable grades which can be discussed in Funnel stage 3.
Table 2 lists all selected grades and their commercial suppliers. The pre-selected materials are PPA with 40 wt% glass fiber (Amodel® FC-1140 L; Syensqo), PA 4.6 with 30 wt% glass fiber (Stanyl® TE200F6-FC; Envalior), PPA+PA blend with 50 wt% glass fiber (Omnix® FC-4050; Syensqo), and UP with glass fiber loading (BMC 1000 FC; LyondellBasell).
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| Table 2: Overview preselected grades and their commercial suppliers. |
Funnel stage 3: Selection discussion with worksheet (qualitative matrix analysis)
In the third funnel stage the matrix analysis takes place. We use the qualitative decision-making process to rank the preselected polymers from Funnel stage 2.
The qualitative matrix analysis has three major steps: in the first step we rank how good each material can fulfil the requirements (0 to 5=best), followed by an assignment of the priorities to each of the requirements (0 to 5 = highest priority). The two steps can be done in reversed order too. In the third step we multiply the requirement fulfilment with the priority and add the values up.
Table 3 summarizes the outcome of the qualitative matrix analysis.
In our case, PPA-GF40 (score: 173 points) and (PPA+PA)-GF30 (score: 157 points) rank number and number 2 respectively, followed by PA 4.6-GF30 (score: 144 points). All three materials should be validated in the Funnel stage 4. Due to the thermal shock and impact performance needed for this application, UP-GF (elongation at break between 0-1.6%) may result in a too brittle material choice and will not be further tested.
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| Table 3: Qualitative matrix analysis for the panhandle. |
Funnel stage 4: Testing, selection of material and vendor
Part and system components, as well as application specific testing with the PPA, PPA+PA, and PA 4.6 materials from Funnel stage 3 takes place in this final Funnel stage 4. Also, processing and tool making are checked to avoid unseen hurdles in the production at a later stage. Final material selection and vendor selection can be done once all the results are obtained.
In our case, we selected the PPA-GF40 for the premium consumer goods segment and the (PPA+PA)-GF30 as a more cost-efficient solution for the standard segment. PA 4.6 can be considered for the standard segment too.
Conclusions
In this example we showed the application of the Polymer Selection Funnel methodology for selecting the optimal food contact grade for panhandle. It is a systematic approach with a resin-agnostic view allowing to consider different material choices.
More polymer material selection examples using the funnel approach can be found here:
My online selection tool:
Polymer Material Selector V1.1
Thanks for reading and #findoutaboutplastics
Greetings,
Herwig
Literature:
[1]
https://www.lyondellbasell.com/495bd8/globalassets/products-technology/advanced-polymer-solutions/technical-data-sheets/bulk-molding-compounds/bmc1000.pdf[2] https://www.matweb.com/search/datasheettext.aspx?matguid=92fbe362c23e4f248abc812a859eb21e
[3] https://www.matweb.com/search/datasheet.aspx?matguid=c9a9ff9a99ca46df81c2e21178e0f2ed&n=1&ckck=1
[4] https://plasticsfinder.envalior.com/en/application/datasheet/2rQz4
