Technical reference
Understanding Adhesive Specifications
What every figure on our datasheets means, what it predicts, and — the part that matters more — what it does not.
Last updated: 2026-09-07
Three figures decide most selections
Base polymer, heat resistance and open time. The polymer sets what the bond can ever do, heat resistance is the constraint that most often rules a product out, and open time is what decides whether it fits your line at all.
Everything else refines the choice. Peel strength — the figure buyers reach for first — is genuinely useful and routinely over-weighted, for reasons set out below.
Will it hold?
Strength properties. Each one is measured a particular way, on particular substrates, when new — read the qualifier as carefully as the number.
Bond Strength (Peel)
≥3.0 N/mm (wood-to-laminate)Force per millimetre of bond width needed to peel one adherend back off the other, usually at 180°.
Tells you
Resistance to something being pulled or picked away from an edge — the way most bonds actually fail in service.
Does not tell you
Say anything about behaviour at temperature, after ageing, or under a static load. A higher peel figure is not a stronger adhesive in general.
Tensile Strength
≥0.8 MPaForce per unit area to pull a cured section apart, straight on. Quoted for sealants rather than for contact adhesives.
Tells you
How much load a sealant bead can carry before it tears.
Does not tell you
Predict adhesion. A sealant can be strong in itself and still let go of the substrate.
Elongation at Break
≥400%How far the cured material stretches before it tears, as a percentage of its original length.
Tells you
Tolerance of joint movement. Paired with tensile strength it describes whether a sealant is soft and stretchy or stiff and strong.
Does not tell you
Equal movement capability — that is a separate, more conservative figure measured on a real joint.
Movement Capability
±25%How much the joint width can change, as a percentage, without the seal failing. The basis of the ISO 11600 class.
Tells you
Whether the sealant suits the joint you designed. Undersize the joint and no sealant grade rescues it.
Does not tell you
Apply to a badly proportioned joint. Depth-to-width ratio matters as much as the figure.
Shore A Hardness
18-25Indentation hardness of the cured material on the Shore A scale.
Tells you
Softness, and by proxy modulus — a low Shore A sealant is the soft, low-modulus kind.
Does not tell you
Substitute for a modulus figure if the specification asks for one.
How will it behave when I apply it?
Process properties. These decide whether the product fits your line, and they are where most complaints originate.
Viscosity
2,500-4,500 mPa·s (brush grade)Resistance to flow, in millipascal-seconds. Water is about 1; honey is roughly 10,000.
Tells you
Whether it brushes, rolls or sprays, and what gun or nozzle it needs. Brush and spray grades of the same product differ mainly here.
Does not tell you
Stay constant. Viscosity rises as solvent evaporates and as the product ages, and falls as temperature rises — a cold warehouse changes it.
Open Time
10-20 minutesThe window after application during which the film is touch-dry and tacky, and the parts can still be brought together.
Tells you
How much assembly time you have, and therefore your maximum panel size and line speed.
Does not tell you
Hold under your conditions. It is measured at 23°C and 50% RH; warm dry air shortens the window and cold humid air lengthens it.
Tack Time
30-60 secondsHow quickly a sprayed film becomes tacky enough to bond. Quoted for spray adhesives, where it is the governing process number.
Tells you
Line speed on a spray application.
Does not tell you
Mean the bond is finished — full strength still takes hours.
Skin Formation Time
10-20 minutesHow long a sealant bead takes to form a surface skin. Tooling has to be finished before this.
Tells you
Your working window for tooling and cleaning up a joint.
Does not tell you
Indicate cure depth. The bead is skinned on top and liquid inside for days.
Full Cure
2-3 mm per 24 hoursRate at which cure progresses inward from the surface, for moisture-cured products, or elapsed time to full strength for others.
Tells you
When the joint can be loaded, moved or tested. A 12 mm deep bead needs four days, not one.
Does not tell you
Scale linearly in deep joints or in dry air — moisture cure slows as it goes deeper.
Reactivation Temperature
65-75°CTemperature at which a dried cement film becomes tacky again so parts can be mated. Specific to footwear and similar processes.
Tells you
Your oven setting. Running cold is one of the most common causes of sole separation.
Does not tell you
Have much tolerance. A few degrees below and the bond never properly forms.
Coverage
3-5 m² per 550ml canArea one unit covers at the recommended application rate.
Tells you
Cost per square metre, which is the number that actually matters when comparing prices.
Does not tell you
Account for both faces. Contact adhesive goes on both surfaces, so plan on roughly half the quoted area of finished assembly.
What am I actually buying?
Composition properties. These are the ones that decide whether one quotation is genuinely cheaper than another.
Base Polymer
Chloroprene Rubber (CR / Neoprene)The polymer that forms the bond. Everything else in the tin carries it, sticks it faster, or makes it cheaper.
Tells you
The ceiling on heat resistance, chemical resistance and durability — set the moment the family is chosen.
Does not tell you
Get adjusted. Changing it is a different product, not a modification.
Solid Content
20-25%Share of the product that remains after the carrier evaporates — the part that becomes the bond.
Tells you
Real cost. A solvent-borne adhesive at 18% solids means most of what you pay freight on evaporates.
Does not tell you
Make a product better by being higher. Higher solids also means higher viscosity, which may not suit your applicator.
Density / Specific Gravity
0.85-0.90 g/cm³Mass per unit volume, or the dimensionless ratio against water. Density carries units; specific gravity does not.
Tells you
Conversion between price per kilogram and price per litre — quotations arrive in both, and comparing them without this is how buyers get the arithmetic wrong.
Does not tell you
Indicate quality in any direction.
Packaging
0.5L, 1L, 3L, 15L tin cans; 200L drumsAvailable fill formats.
Tells you
Whether it runs on your equipment and how many units fit a container. Regional formats differ — North America works in ounces and gallons.
Does not tell you
Come free to change. A different fill format is tooling and line setup, quoted as an OEM run.
Where can it go?
Constraint properties. Any one of these can rule a product out before performance is discussed at all.
Heat Resistance
−20°C to +120°CService temperature range over which the bond retains useful strength.
Tells you
Whether it survives your worst case — a parked car roof cavity, a container in the tropics, a wall next to a heat source.
Does not tell you
State the dwell time. "Resistant to 100°C" may mean one hour, not the 500 hours your application needs. Ask.
Flash Point
≤−4°CLowest temperature at which the liquid gives off enough vapour to ignite.
Tells you
Dangerous-goods classification. Below 23°C makes it UN 1133, Class 3 — which changes shipping, storage and insurance together.
Does not tell you
Apply in the same way to water-based or solvent-free products. They usually have no flash point to report, but their transport position is still read from SDS section 14.
VOC Content
<50 g/LVolatile organic compound content, by the basis the governing rule defines.
Tells you
Whether it can legally be sold into your market — but only when quoted against a named instrument and category.
Does not tell you
Mean anything on its own. A figure without the rule, the category and the basis (with or without water and exempt compounds) is not comparable to a limit.
Cure System
Neutral (Oxime / Alkoxy)What chemistry the sealant cures by, and therefore what it gives off while curing.
Tells you
Substrate compatibility. Acetoxy releases acetic acid and is wrong on metal, mirror, marble and concrete.
Does not tell you
Affect the cured properties much. It is a compatibility question, not a strength one.
Shelf Life
12 months (sealed, 5-35°C)How long the sealed product stays within specification under the stated storage conditions.
Tells you
How much life you have — from date of manufacture, not from delivery.
Does not tell you
Survive bad storage. A product stored hot can fail inside date, and a month past date is often still serviceable. Test, do not assume in either direction.
Pressure-sensitive adhesives use three different figures
Labels, tapes and protective films are specified by tack (how readily they grab), peel adhesion (the force to remove them) and holding power (how long they carry a load without sliding). Each has its own published methods — FINAT, PSTC and ASTM among them — and values from different methods, surfaces or dwell times cannot be compared. Our acrylic adhesives page sets out which method measures what.
Coat weight belongs next to all three: dry coat weight is roughly the wet coat weight times the solids fraction, and a figure measured at one coat weight says little about another.
A number without its method is not comparable
This is the practical conclusion of everything above, and it applies to our figures as much as to anyone else's. Three things have to match before two numbers can be compared:
| Check | Why it changes the number |
|---|---|
| The property | Peel (N/mm) and shear or tensile (MPa) are different measurements in different units. A shear figure always looks larger. |
| The substrate pair | The same adhesive gives very different peel figures on wood-to-laminate, leather-to-rubber and rubber-to-EVA. |
| The standard and conditions | Test speed, temperature, cure time before testing and specimen preparation all move the result. |
Including from us
Our peel figures name a substrate pair — ≥4.0 N/mm on rubber-to-EVA for the PU shoe grade, for instance — but the test method and conditioning are not printed with them yet. Until they are, you are entitled to ask for both before you compare us against another supplier, and we would rather you did. A buyer who compares properly ends up with the right product, which is cheaper for both of us than one who does not.
Frequently asked questions
What does solids content mean in an adhesive?
What is open time and how is it different from tack time and cure time?
What does mPa·s mean in an adhesive viscosity figure?
Is N/mm the same as MPa for bond strength?
Why do your peel strength figures name a substrate?
A supplier quoted a higher number than yours. Does that make their product better?
Putting the numbers to use
- What the base polymer actually decides
Chloroprene, SBS, PU, water-based and silicone — heat, flex and durability are set the moment the family is chosen.
- Full specification tables for all six lines
The datasheets these figures come from, product by product.
- Two products compared spec by spec
What the peel and heat figures mean side by side on real grades.
- Why a VOC figure needs its instrument named
A number without the rule, the category and the basis is not comparable to a limit.
- Storage, shelf life and what heat does to it
Why a container crossing the tropics at 60-70°C is the hardest storage condition your adhesive will see.
- Eight checks before you pick a supplier
Manufacturer or trader, grade-level test data, VOC position and dangerous-goods handling — apply them to us too.
- Review our certifications and test reports
ISO 9001, ISO 14001, REACH statements and SGS reports, and what each one covers.
- Browse the full technical library
Every reference page and guide, grouped by the question it answers rather than by date.
- Put your own brand on it — OEM and ODM
Custom labels, cartons and formulation adjustments from our existing lines.
- Look up a term and its other names
Non-acid silicone is neutral cure; liquid nails is grab adhesive. Fifty terms with their synonyms.
- Pack formats, and your market’s versions of them
Tins, drums, aerosols and cartridges — with the metric to US conversions that catch importers out.
- Send a specification and get a quote
Substrate, volume and destination market are enough for us to price it.
Send us a datasheet you are trying to read
Yours, a competitor's, or one of ours. We will tell you which figures are comparable, which are missing their method, and which of them actually governs your application.
