Five datasheet phrases and the number each one needs behind it

A datasheet for a new sheet material often reads well and says little. Datasheet phrases such as strong, flexible or tested are easy to write and hard to check. This note takes five phrases that turn up again and again, and for each one it says what a team should ask for so that the phrase becomes something it can test. It is written for R&D engineers and material buyers, and it applies to any supplier.

1. “Strong” or “durable”

Strength is not one number. A tensile result gives the force at break and how far the sheet stretches. Flex resistance gives how many bends it survives. Abrasion gives how it wears under rubbing. A sheet can do well on one and poorly on another.

Ask for: the property named, the unit, the method, the direction of the specimen (length or width), the number of readings and the spread between them. Listings often name ISO 3376 for tensile work on leather and ISO 32100 for flex. Treat these as leads, not as answers, and confirm the edition with the laboratory.

2. “Flexible”

Flexible compared with what, and at what thickness? A thin sheet bends easily whatever it is made of, so a flexibility claim without a thickness is half a claim. Ask for the thickness as a mean with its range, and for the flex test result at that thickness, dry and after wetting. If the sheet will be folded at a seam or a corner, say so, because the test should resemble that use.

3. “Water resistant”

This phrase hides at least three questions. Does water run off the surface? Does it soak in, and how much mass does the sheet gain? Does the sheet change size or stiffness after it dries? Materials made from plant or microbial cellulose may react to water differently from coated fabrics, so these questions carry weight for them.

Ask for: the soak time and temperature, the mass gain in percent, the size change after drying and a note on whether the surface layer was part of the specimen. We found no method number for water absorption in the sources behind this site, so agree on a method with the supplier and write it into your plan.

4. “Tested”

“Tested” is the phrase most in need of a second look. By whom, on what and when? A strong reply names the laboratory, the method with its edition, the date and the lot from which the specimens came. A weak reply says “tested to international standards”. Ask also whether the specimens were cut from the sheet you will receive or from an earlier version. A result from an earlier version describes an earlier version.

5. “Made from” a named raw material

This phrase tells you the start of the story. It does not tell you the end. A sheet can start from one raw material and finish with a coating, a backing, a dye and a softener. Ask for every layer by name, the approximate share of each by mass and the role of any synthetic polymer in the stack. A supplier that cannot give this yet should say so, which is useful information in itself.

What a good reply looks like

A good reply has four parts: a number, a unit, a method with its edition and a statement of which specimen it came from. If one part is missing, ask again. If the supplier cannot supply any part, record that as “not available” and move on. An empty cell is more honest, and more useful to you, than a vague one.

Keep a ledger

For each supplier, keep a simple ledger with one row for each of the five datasheet phrases and four columns: what was claimed, what was asked, what came back and the lot it refers to. A few months later, when a result surprises you, the ledger shows whether the surprise was in the sheet or in the claim.

A template you can copy

We put the five datasheet phrases, and a sixth about development stage, into an evidence request template. It is free to copy and applies to any supplier. The template also shows where Kora has published nothing yet, so you will know which answers to expect on request and which are still open. Kora’s coconut-derived sheet has no published test data and no stated development stage, and the template says so plainly.

Ask us

If you want to send Kora your own list of properties and the standards behind them, use the contact page. Name the application and the properties you must measure, and we will tell you what Kora can state in writing, what it cannot and what would need new testing.