Hanwha Material Selection Guide: EVA Foam Armor, PTFE Product, and Polypropylene vs Polyurethane

If you're comparing polymer materials, start with the failure mode you're trying to avoid, not with a datasheet. I work in quality/compliance at Hanwha, and I review about 200 material specifications a year. The question “which material is better?” usually has no single answer. The useful question is “which failure are you preventing?”

If you've ever approved a material because a chart said “high impact” and then watched it crack in a drop test, you know why I'm obsessive about test conditions. Let's separate three common requests: EVA foam armor, PTFE product selection, and the polypropylene vs polyurethane comparison.

Three questions to classify your part

Before I recommend a Hanwha material, I ask three things:

• What will make the part fail?
• What temperature, chemical, load, or humidity does the part face?
• Can you test actual samples before full production?

Those answers usually put you in one of three buckets:

1. Impact protection and shape recovery → EVA foam armor is worth investigating.
2. Chemical resistance, heat, low friction, or creep → start with a PTFE product.
3. Repeated flex, structural load, or abrasion → work through the polypropylene vs polyurethane trade-off.

Scenario A: Flexible impact protection and EVA foam armor

When you're making EVA foam armor, the property that matters is not maximum tensile strength. It is controlled compression. A good panel should absorb an impact, distribute the force, and recover without taking a permanent dent. That is why density, cell structure, and compression set matter more than the first page of marketing numbers.

I am not talking about ballistic body armor here. I am talking about cosplay armor, training props, padded equipment, and protective packaging. One common failure is when the foam feels soft in the hand but collapses under repeated impact. Another is when it cracks during thermoforming or sharp curves.

I learned this the hard way. I said “soft foam” in an inquiry. The sample maker heard “weak foam.” Result: a sheet that felt soft but dented permanently and tore when bent over a tight edge. What I should have specified was foam density, Shore hardness, and compression set. Let me rephrase that: use numbers, not adjectives, when you ask for Hanwha EVA grades.

If I remember correctly, flexible EVA foam often starts around 20% VA content, but don't quote me without checking the current Hanwha EVA datasheet. The right value depends on the foaming process and the final density. On the Hanwha portal, you can compare those columns instead of relying on a supplier's verbal summary.

Scenario B: High heat, chemicals, or sliding surfaces and PTFE product selection

If the failure would start with chemical attack, heat, or friction, a PTFE product is often the right family to examine. PTFE is known for broad chemical resistance, low friction, and a wide service temperature range. Those are real advantages. But the phrase “PTFE product” covers different forms, and those forms do not behave the same.

The surprise for many engineers is not that an unfilled PTFE product survives an aggressive solvent. The surprise is that it can deform under sustained load. I saw an unfilled PTFE gasket creep out of a flange in a 2024 line audit. It did not fail chemically; it flowed under pressure. A filled PTFE grade solved the problem.

When you pull a PTFE product datasheet, check the filler type and the manufacturing form. Skived film, molded sheet, and filled compound have different porosity, creep, and wear behavior. Let me be specific: if your assembly involves tight clamping, ask for creep data. The cheapest PTFE product is not cheap if it causes a shutdown.

The most frustrating part of PTFE selection is vague specifications. “Good chemical resistance” does not tell you the thickness tested, the temperature, or the soak duration. I review a lot of PTFE product claims through the Hanwha portal, and I still verify the exact test method before approving a material.

Scenario C: Structural loads, wear, and repeated flex: polypropylene vs polyurethane

The polypropylene vs polyurethane question shows up when a part carries a load, slides, or flexes many times. It is not a winner-takes-all contest. Hanwha's portfolio doesn't cover every PU grade on the market, and that is fine. The goal is to match the material to the dominant failure mode.

Choose polypropylene when you need low density, moisture resistance, chemical resistance, or a living hinge that can survive many cycles. A good PP grade is not as elastic as polyurethane, but it does not need to be. In many structural and packaging applications, PP is the quieter long-term option.

Choose polyurethane when the main threats are abrasion, tearing, or high-strain rebound. PU can absorb a beating and return to shape in ways that PP cannot. But PU is usually heavier, often costs more per kilogram, and can be more sensitive to moisture at high temperatures. What was best practice in 2020 may not apply in 2025.

I used to accept “polyurethane is tougher than polypropylene” as a general rule. Then in 2024 we ran a hot-water wear comparison and a PP grade outlasted the PU because the PU softened. It surprised me too. The fundamental principle did not change—test the actual service condition—but the old rule was too broad.

When I'm asked about polypropylene vs polyurethane, I use the Hanwha portal to pull PP data, and then I ask the PU supplier for data measured under the same standard. Comparing Izod with Charpy, or dry samples with conditioned samples, is how material decisions go wrong.

How to decide where you belong and what to do next

Here is a quick gut check, take it from someone who has reviewed too many failed samples:

• If the part is soft, shaped from foam, and supposed to absorb impact, start with Scenario A and specify compression set.
• If the failure would be chemical, thermal, or creep-related, start with Scenario B and ask for the PTFE product test conditions.
• If the failure would happen under repeated movement, load, or abrasion, work through Scenario C and compare numbers from the same test standard.

As of February 2025, the Hanwha portal is where I tell customers to verify current property values instead of trusting an old datasheet that has been copied from one inbox to another. Materials get revised. Test methods get updated. A spec that was correct for your 2024 project should be rechecked before you scale it.

Trust me on this one: the extra day spent defining the failure mode saves a ton of time later. And if someone still insists there is a single best material for all three scenarios—EVA foam armor, PTFE product, and the polypropylene vs polyurethane problem—politely ask them for their test data.