PolyArylAmide (PARA) - Part Marking Codes Following ISO 1874

Hello and welcome to this part marking post for semi-aromatic PolyArylAmides (PARA or MXD6) following the ISO 1874, which established a system for designation of Polyamide thermoplastic materials.

PARA is a high-performance polymer combining several excellent properties such as low water uptake, high modulus levels also after moisture pick up, and best surface among all Polyamides due to its fine crystallisation in the surface regions (even with high glass fiber loadings). During the design phase of your injection mould, question may rise on which part makring code should be used. Here, Table 1 can help you which shows the designations for the most important PARA compounds. 

Table 1: Plastic part marking codes for PARA following ISO 1874

Check out my plastic part marking introduction post (incl. miniguide for download) here. 

Thanks for reading and #findoutaboutplastics

Greetings, 

Herwig 

Interested to talk with me about your polymer material selection, sustainability, and part design needs - here you can contact me 

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog – check out the start here section

My YouTube channel

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Literature:

[1] ISO 1874:2010

[2] Solvay - Ixef Processing Guide

Sodium-ion Batteries - How Plastic Waste Helps to Produce Carbon Anodes

Sodium-ion Batteries - How Plastic Waste Helps to Produce Carbon Anodes

Hello and welcome to this new blog post in which we discuss the role of plastic waste in making Sodium-ion batteries.

Why Sodium-ion batteries?

Lithium-ion batteries have established themselves as the major power supplier for electric cars and high performance polymers play a key role in making such batteries as well as maintaining the safety during use (for example battery cages). 

In past years a new type of battery gained traction. It is the Sodium-ion battery. Chinese automotive company BYD established a  joint venture to begin mass producing its nascent Sodium-ion EV batteries. So there is definitely some momentum in this kind of battery. The idea is to use such batteries for low range cars and have the long range handled by Lithium-ion batteries. 

What are the major advantages of Sodium-ion batteries?

Cost advantage: Since we need Natrium instead of Lithium, supply is secure and at a predictable price level too. No cobalt or copper current collector is needed. 

Safety: Sodium-ion batteries showed excellent testing results. They are safe at low temperatures and as well as at higher temperatures which allows to reduce the safety installations in the car. Furthermore, they can be transported and stored in their low energy state at 0V.

Sustainability: Sodium is an abundant element and we do not need Lithium, cobalt or toxic lead for such kind of batteries anymore. 

Scalability: They have the same operation principle and format as Lithium-ion batteries and can be manufactured at existing battery plants. Also, different chemistries are possible. 

Downsides: They are around two thirds heavier compared to Lithium-ion batteries, however research is on it to lower the weight and increase performance. 

PS, PA, and PET - the potential recycling materials for carbon anodes

Researchers at the Department of Chemical Engineering at Imperial College London propose the formation of hard-carbon electrode materials through the autogenic conversion of plastics waste at temperatures between 300°C to 700°C [2].

The focus is on recycling of Polystyrene (PS), Polyamide (PA), and Polyethylene terephthalate (PET). Increasing the carbon output of PS is done over cross-linking it in a first step. Then carbonization at 1000°C and 1500°C takes place using up to five cycles. The next steps in their project include the finding of the optimum autoclave temperature for each polymer and generating a Life-Cycle Assessment (LCA) to compare the plastic waste based carbon anode to standard industrial made carbon anodes. 

Conclusions

Sodium-ion batteries will be found in some of the EV segments (lower range EVs). It could be demonstrated that an everyday plastic waste can be used to make curial elements, the carbon anodes, in Sodium-ion batteries.

Thanks for reading and #findoutaboutplastics

Greetings

Herwig 

Interested to talk with me about your polymer material selection, sustainability, and part design needs - here you can contact me 

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog – check out the start here section

My YouTube channel

My personal website

Literature:

[1] https://www.youtube.com/watch?v=nKHItAMEQks

[2] "Sodium-ion Batteries using Carbon Anodes Derived from Plastic Waste" by Dr Maria Crespo Ribadeneyra , Department of Chemical Engineering.https://onedrive.live.com/?authkey=%21AGpXc6zuEqieuK8&id=6CA464254DD4264A%211832&cid=6CA464254DD4264A&parId=root&parQt=sharedby&o=OneUp

[3] https://www.youtube.com/watch?v=9mSn9s0lwsY

[4] https://electrek.co/2023/06/12/byd-joint-venture-mass-producing-sodium-ion-ev-batteries/

Plastic Part Design for Recycling - The Important Role of Part Marking Codes

Hello and welcome to a new blog post in which we discuss recycling considerations for plastics part design. 

Overview on recycling methods

To gain a better understanding of the topic of recycling, we first have a look at the six different recycling methods. 

1. Product reuse: designers aim for usage of  the product more than once. An example are returnable bottles. 

2. Traditional disposal methods: in this case the product is dumped to landfill sites. It is not an optimal scenario for plastics, except for biodegradable plastics. Plastic landfilling is already forbidden in most European countries due to rising costs and public opinion. 

3. Treatment and dumping: in this case, plastics are pre-treated and all dangerous pollutants are removed before dumping.

4. Mechanical recycling: the process of mechanical plastics recycling consists of collecting, sorting, cleaning and reprocessing into plastics pellets which can be used for new products (upcycling or downcycling). 

5. Feedstock recycling: breaking down the polymers into monomers which then can be in turn polymerized again or used for other purposes. 

6. Energy recovery: burning plastics to recover their stored energy. This is a good option for low-values mixes and soiled wastes. In general, plastics have a higher calorific value than coal. 

Plastic part marking codes

In past years, plastic part designers considered the part styling, safety, and cost efficiency as major points to pay attention to. Additionally, we now have the usage of low carbon footprint materials, together with the objective to enable easy recycling after end usage. 

Enabler for proper recycling is the need to identify the plastics used in the part at the end of product life. Mixing different plastics makes it harder for mechanical recycling methods. Therefore, part marking standards were established. In the lead of this is the SPI resin identification code, which represents chasing-arrows with a number from 1 to 7 (Figure 1):

1=PET

2=HDPE

3=PVC

4=LDPE

5=PP

6=PS

7=Other

Figure 2: SPI resin identification codes for commodity plastics

This system is good for packing applications with commodity plastics such as LDPE and PP. However, since most of us deal with engineering parts, there are some more part marking codes which we can use. 

For example, there is the ISO 1043 which consists out of four parts and covers the base polymers, fillers, additives, flame retardant, and plasticizers. Figure 2 shows an example of using this part marking standard. More examples can be found here.

Figrue 2: Part marking example of a Polyamide 6 with glass fbers and flame retardant

Supporting this topic, I  made a miniguide (download here), and detailed blog post (here) allowing to deep-dive into the basics. 

Conclusions

Using such part marking standards allows for easier collecting of used parts and creating post industrial recycled (PIR) materials as well as post consumer recycled materials (PCR). 

Thanks for reading & #findoutaboutplastics

Greetings,

Herwig 

Interested to talk with me about your polymer material selection, sustainability, and part design needs - here you can contact me 

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog – check out the start here section

My YouTube channel

My personal website

Literature:

[1] https://www.iso.org/standard/50590.html

[2] Tangram Plastics Design Guide

5 Important Design Rules for your Next Plastic Injection Moulded Part Project

Hello and welcome back to a new blog post. In today’s post we highlight some important design guidelines for successful injection moulded parts. 

Since part design is one of the five critical success factors for obtaining an injection moulded part, it is important to follow the design recommendation for plastics. All factors (Part design, Material selection, Mould design and construction, Moulding machine selection, and Moulding process) can be summarised in the Polymer Product Pentagram. 

In general there are 10 holy design rules and today we picked the 5 most important ones. 

Overview - 5 important design rules for injection moulded plastic parts

1) Uniform wall thickness: aim to have a wall thickness as thin as possible as well as uniform as possible. Avoid your part to go from thin to thick regions (worse) and thick to thin (also bad). Best case scenario is a thin wall with ribs. For reinforced plastics wall thickness should range between 0.75 mm to 3 mm maximum. For unfilled plastics, you can aim for 0.5 mm to maximum 5 mm. 

2) Rib design: as I have mentioned to add ribs to your walls, it is important that they have the right geometrical dimensions too. Let us take a part with no ribs as an example. Such a part consumes approximately 15% more material than a part with ribs and the cycle can be up to 70% longer compared to the thinner part with ribs. For unfilled materials, rib thickness should be less than 70% of the nominal wall thickness. If you have a rib thickness larger than 70% of the wall thickness, material gets drawn away from the center of the opposite wall during cooling and as a result internal voids or sink opposite of the rib occur. Furthermore, ribs are getting effective when they are 5-10 times higher than the nominal wall thickness.

3) Draft angles on ribs: as important as the rib thickness is, draft angels need to be placed in order to eject the part after moulding. Usually a minimum draft angle of 0.5° is necessary. 1° to 2° is commonly applied according to material supplier recommendations. If you use glass-fiber plastics, a higher draft angle might be better. The same is true for low shrinkage materials. On the other hand, highly flexible materials such as PVC need less draft angles. Also, if you have rough surfaces on your part, recommendation is 1° for each 20 mu surface roughness. 

4) Radius: avoid sharp corners and make a radius, together with fillets. In general the radius should be 0.9 to 1.2 times the nominal range of the part. 

5) Undercuts: there are four different design features where undercuts play a role. There can be a window in a side wall, an overhang above the bottom wall of the part, a horizontal boss, and a snap finger. However, if possible try to avoid them since a more mould mechanism must be considered, as well as machined to have a proper ejection of the finished part. 

I hope that these 5 design rules will help you in your next plastic part project and if you have any questions around your part design or want to create your own plastic compound, pl. reach out here to support you. Also, if you need plastic sample material for testing, you can reach out here. 

Thanks and #findoutaboutplastics

Herwig 

Interested to talk with me about your polymer material selection, sustainability, and part design needs - here you can contact me 

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog – check out the start here section

My YouTube channel

My personal website

Literature:

[1] https://www.findoutaboutplastics.com/2021/10/rule-of-thumb-for-plastics-part-design.html

[2] Design guide for plastics by Tangram