How to read a packaging tape data sheet

Two quotations arrive for the same carton tape. One data sheet gives peel adhesion as 40 oz/in. The other gives it as 11 N/25 mm. Which tape sticks better?

On paper, neither. Convert one into the other and they are almost exactly the same number.

A tape data sheet is useful only when you read each value together with its test method, its test conditions and its unit. Read that way, it tells you whether a tape suits your job and whether every delivery matches the last one. Without them, two sheets cannot be compared at all.

We have been making packaging in Jaipur since 1997, and tape is a big part of what we make. I have written this guide for our customers. It goes through the lines you will find on a typical packaging tape data sheet, the test behind each one, and what it means on your packing line.

The method works for any maker's sheet, ours included.

If you buy from us, ask us for the sheet of your product and read it the same way.

In the examples I use a public data sheet from 3M, because it is detailed and anyone can download it.

Start with one question: typical or minimum?

Most data sheets show typical values. These are averages from the maker's own tests. They are not promises for every roll.

3M is open about this. Its data sheet for Scotch 371 box sealing tape (revised September 2024) says its values are typical and should not be used for specifications. I respect a maker who prints that line.

A minimum value is different. It is a number the maker agrees that every lot will meet. On this point I am strict. If a property matters to your job, ask for a minimum with a tolerance, in writing.

Then check the revision date on the sheet. An old sheet may describe an older product.

Thickness

Thickness (also called caliper) is measured under slight pressure, as the Pressure Sensitive Tape Council's glossary explains. The usual method is ASTM D3652/D3652M-01(2020), published by ASTM International.

You will see it in microns, millimetres or mil. One mil is a thousandth of an inch, which is 25.4 microns.

Look for two figures. The 3M 371 sheet lists a backing of 0.03 mm and a total thickness of 0.046 mm (1.8 mil). The backing is the film. The rest is adhesive.

A single "total" figure does not tell you how the thickness is shared between the two. Ask us, or any supplier, for both.

Peel adhesion

Peel adhesion is the force per unit of width needed to peel the tape back from a surface. Data sheets often call it "adhesion to steel".

The common methods are these:

1. ASTM D3330/D3330M-04(2025), ASTM International. Method A peels the tape at 180 degrees from a stainless steel panel.
2. PSTC-101, from the PSTC test methods manual (17th edition). It peels at 180 degrees at 5 mm per second.
3. FINAT FTM 1 and FTM 2, from the FINAT Technical Handbook (11th edition, 2025). These peel at 180 and 90 degrees at 300 mm per minute. You will see them mostly on label stock.
4. IS 8402:1987, the Bureau of Indian Standards method for sampling and testing pressure sensitive tapes. It conditions the rolls at 27 ± 2°C and 65 ± 5% relative humidity, lets the tape rest on the steel plate for 10 minutes, and reports the result in kg per cm of width.

Now read the conditions printed beside the value. The 3M 371 sheet gives 43.8 N/100 mm (40 oz/in), on stainless steel, at 23°C, peeled at 180 degrees, after a dwell time of 72 hours.

Dwell time changes the result considerably. It is how long the tape sat on the panel before the test. Adhesive keeps flowing into the surface for hours, so a 72 hour value will usually be higher than a 10 minute value for the same tape. For its VHB foam tapes, 3M's data sheet for VHB 4951 (September 2024) says about half of full strength is reached after 20 minutes, 90% after 24 hours and full strength after 72 hours.

This is the line I would read most carefully. The ASTM D3330 standard itself says its results cannot be used to compare two tapes of the same type from different makers for their ability to stick to a surface. The reason is physical. The area of adhesive under stress changes with the stiffness of the backing and the firmness of the adhesive. The standard also warns that peel values usually have no direct link to a real job.

So I suggest you use peel adhesion for what it does well. It shows whether this lot of a tape matches the last lot of the same tape.

To compare two makers, test both on your own cartons.

Tack

Tack is the ability of an adhesive to grab a surface under very light pressure. It decides whether tape grabs a carton at once when a packer runs it on by hand.

Two tests are common:

1. Loop tack, under ASTM D6195-22 or FINAT FTM 9. A loop of tape touches a panel and is pulled away. ASTM notes that stiffer backings give higher loop tack values, so a thick tape and a thin tape do not compare fairly.
2. Rolling ball tack, under ASTM D3121-25. A steel ball rolls down a ramp onto the adhesive. ASTM says this test is meant for quality control and is not recommended for specifying end use products.

For carton tape, I would ask for loop tack rather than rolling ball.

Holding power

Holding power, or shear adhesion, is how long a strip of tape holds a hanging weight before it slips or falls. The method is ASTM D3654/D3654M-06(2024). Procedure A uses a steel panel. Procedures B, C and D are meant for tapes that close fibreboard boxes.

A holding power figure means nothing without four facts: the weight, the area of tape, the surface and the temperature. The 3M 371 sheet gives 3,500+ minutes on fibreboard. A plus sign like this normally means the sample was still holding when the test was stopped.

ASTM adds a warning that every carton buyer in India should hear. Fibreboard surfaces vary between mills, between batches from one mill, and even within one batch. A result on one board does not promise the same result on another.

For carton tape, we suggest you ask for holding power on fibreboard, not on steel.

Tensile strength and elongation

Tensile strength is the force needed to break a unit width of tape. Elongation is how far the tape stretches before it breaks, as a percentage of its length. Both come from ASTM D3759/D3759M-05(2025) or PSTC-131.

The 3M 371 sheet gives 385 N/100 mm (22 lb/in) in the machine direction and an elongation of 160%. Machine direction means along the length of the roll. Some sheets also give a cross direction value, across the roll.

Tensile strength matters most for heavy cartons and for bundling. It depends on the backing far more than on the adhesive.

Converting the units

Convert both sheets to one unit before you compare anything. This table covers the force-per-width units you will meet on adhesion and tensile lines.

For thickness, 1 mil is 25.4 microns.

I suggest you keep this table in your purchase file. It removes much of the confusion when an imported tape is quoted against a local one.

Which numbers matter for which job

No tape is best on every line of its data sheet. These are the lines we suggest you read first for each job.

For double-sided and masking tapes, the guides on choosing double-sided tape and masking tape grades go further.

A five-minute check you can do on any data sheet

You do not need a laboratory for this. You need the sheet and a pen.

1. Is a test method named next to every value? A value with no method is an opinion.
2. Are the conditions given: surface, dwell time, temperature and peel angle?
3. Does the sheet say whether values are typical or minimum?
4. Is there a revision date, and is it recent?
5. Are the units the same as on the other sheet you are comparing? If not, convert them with the table above.

If a sheet fails three of these five, I would not use it to choose between suppliers.

Run the same check on our sheets too. We would rather be questioned than misread.

A data sheet is like the mileage figure in a car brochure. It is a real measurement, taken under fixed conditions. Your own road will give you a different number.

That is why the last step is always a trial on your own cartons, with your own packers, in your own season. If tape fails on the line, the troubleshooting guide lists simple tests to find the cause.

What I suggest you ask your supplier

Whoever you buy from, these five requests will make your next comparison fair:

1. The test method and conditions behind each value.
2. Minimum values, with tolerances, for the two or three properties your job depends on.
3. Backing thickness and adhesive type, as well as total thickness.
4. Month of manufacture and batch number on every carton. IS 13262:1992, the Indian specification for plastic-backed tapes, already asks makers to mark both.
5. Storage conditions and shelf life. The guide on storing tapes and films explains why these matter.

I will be honest about one limit. A data sheet, ours or anyone else's, describes tests done in a laboratory at 23 or 27°C on clean steel. A godown in a north Indian January is not that laboratory. The sheet helps you shortlist a tape, and your own trial decides.

If you buy from us and any value on our sheet is unclear, write to us through the contact page with the product name and batch number. I would rather explain a number twice than have you guess it.