Covestro vs Teijin, PP, TPU Sneakers, and ABS to PVC: A Polymer Sourcing Reality Check

I'm a quality compliance manager at Covestro. I review material specifications before they go into production—roughly 150 grades a year. In 2024, I rejected about 13% of first shipments because of lot variation, not because of how the part looked. So when I get questions like 'what's the best material?' I usually answer with another question: 'What failure are you trying to avoid?'

There is no universal best material. There are only matching scenarios. Here are the four I see most often in B2B polymer selection:

• Optical clarity, impact resistance, and heat resistance — that's polycarbonate territory.
• Low cost, low weight, chemical resistance — that's polypropylene (PP).
• Flexibility plus abrasion resistance — that's TPU, including sneaker soles.
• Joining two different plastics — like ABS to PVC, that's a bonding/fastening question.

The PC option: where Covestro and Teijin fit

Polycarbonate is my default when a part has to stay transparent, survive impact, and take heat without losing shape. That question usually comes in as 'market share polycarbonate Covestro vs Teijin.' Honestly, I'm not sure those numbers are stable enough to quote without a footnote. Most 2024 industry estimates (ICIS, Plastics Today) put Covestro in the 15–20% range globally, with Teijin in the single digits—but Teijin is much stronger in optical media and specialty films. So the real question is: which supplier can match your exact spec, not which one is bigger.

One phrase that keeps showing up in search is 'Covestro board and sustainability.' It is ambiguous, and it matters. On the corporate side, Covestro's Board of Management has made climate neutrality a stated goal for Scope 1 and 2 emissions by 2035 (Covestro Annual Report, 2024). On the product side, Covestro also makes polycarbonate board products, and some can be sourced with certified circular feedstock. Both angles affect procurement, but neither replaces a mechanical spec.

What do I actually check for PC? Melt-flow rate, tensile strength, Izod impact, and lot traceability. ISO 527-2 and ISO 180 are the references I use. In my first year, I made the classic rookie mistake: I assumed two 'standard PC' grades from different suppliers were identical. They weren't. The melt flow was 10 on one and 22 on the other, and thermal cycling exposed it. We rejected the lot. I also approved a cheaper off-spec batch once to save about $2,000 on a frame project. It was penny-wise and pound-foolish: rework and delay cost us about $18,000. Now lot consistency is written into every contract.

The PP workhorse: low cost, low weight, chemical resistance

If you look at the polypropylene PP market, it's a different game from PC. Global demand is in the 70-80 million tonne range (Source: IHS Markit, 2024), so the supply chain is huge and scale changes the economics. PP makes sense when you need low weight, good chemical resistance, a more forgiving price, and you can live without glass-like clarity and high continuous heat resistance.

The catch is that PP is difficult to bond and it creeps under sustained load. A red flag for me is any supplier who promises a 'structural' PP part without accounting for creep. If your part lives in an ordinary service environment and doesn't need clarity, PP is often the no-brainer choice. If you want to bond it, plan for surface treatment or mechanical fastening.

If you need flex: TPU sneakers and wearables

TPU has a different personality. Thermoplastic polyurethane is flexible, abrasion-resistant, and can be transparent. That's why TPU sneakers are everywhere: you can mold translucent midsole shapes that keep snapping back, and the material holds up to rough surfaces.

When I audit a TPU spec, I don't just confirm the color. I ask for Shore hardness and compression set. Softness alone doesn't make a good sole; if the foam takes a permanent set, that's where cracking starts. Covestro's bio-based TPU and recycled-content TPU are real options, but I treat them as additional specs, not as a reason to skip the testing.

Can you glue ABS to PVC? Yes, but not with general-purpose glue

This is the question I get most from prototype shops and maintenance teams. Good news: yes, you can join ABS to PVC. But 'glue' is the wrong word—solvent welding or a specialty plastic adhesive is more accurate.

For pipe and fittings, use a solvent cement made explicitly for ABS-to-PVC transitions. The joint must be dry, clean, and stress-free. In a Q4 2023 failure review, the root cause was standard PVC cement on an ABS-to-PVC joint; it looked fine for a week, then failed under pressure. For sheet or non-pressure parts, a two-part acrylic adhesive designed for mixed plastics is a better bet. And if the joint carries real load, don't rely on glue alone—use a transition fitting or mechanical fastening.

How to tell which scenario you're in

Here's the filter I use in procurement reviews:

1. Does the part need transparency, impact resistance, and heat resistance? If yes, compare polycarbonate grades—Covestro and Teijin both make strong candidates.
2. If low weight, low cost, and chemical resistance matter more, and clarity isn't key, PP is the workhorse—but design for creep and bonding challenges.
3. If the part has to flex and survive abrasion, like a sneaker sole, TPU is the natural candidate.
4. If the problem is joining ABS and PVC, treat it as a joining problem first, not a material selection problem.

If someone gives you one universal answer without asking about load, temperature, chemical exposure, UV, or joining method, get a second opinion.

Bottom line: I don't care whether you choose Covestro or Teijin for a PC part as long as the datasheet and lot traceability match. If you want a broad polymer range and documented sustainability, Covestro is a reasonable place to start. If you need optical film or specialty glass-like grades, Teijin deserves a hard look. If you need PP, stop reading PC content. If you need TPU sneakers, design for flex fatigue. If you need to glue ABS to PVC, buy the right cement.

This framework covers maybe 80% of the requests I review. If you're in the other 20%, you'll need real-world testing under load, temperature, and chemical exposure. That's not a dodge—it's how you avoid a costly redo.