How should you read a PSA datasheet?
A PSA datasheet reports a handful of numbers measured under fixed conditions in the supplier’s laboratory. Read them as a comparison between grades tested the same way, not as the values your finished tape will reach. Coat weight, the backing, drying, the surface and time all move them, which is why our catalogue calls its values indicative.
What basis are our values tested on?
Our peel, tack and shear values are measured on adhesive coated onto 25 µm (1 mil) PET film at 25 ± 2 gsm dry coat weight. The tests follow Pressure Sensitive Tape Council (PSTC) methods, with peel tested against a stainless-steel plate.
What does 180° peel adhesion measure?
PSTC-101. A 25 mm strip of the coated film is pressed onto stainless steel and pulled back on itself at 180°, at 300 mm per minute, and the force is averaged over the pull. We report it in gram-force per 25 mm. Our catalogue prints the same numbers in g/inch, which is the same basis to within about 1.6%.
Peel measures adhesion: how firmly the tape holds on to the surface. Permanent tapes want a high peel; masking and removable tapes want a low, controlled one. For scale, 1,000 gf/25 mm is about 9.8 N/25 mm, or 3.9 N/cm.
What does loop tack measure?
Loop tack shows how quickly the adhesive grabs. In a loop tack test, a loop of the coated film, adhesive side out, is lowered onto a plate with no added pressure and pulled straight off; the force to free it is reported in gram-force per inch. Hand-applied tapes, masking tapes and labels need a high loop tack.
What does rolling-ball tack measure?
PSTC-106. A steel ball rolls down a short incline onto the adhesive, and the distance it travels before it stops is measured in centimetres. A shorter distance means a tackier adhesive.
What does shear (holding power) measure?
PSTC-107. A 25 × 25 mm overlap of the tape is hung from a plate under a 1 kg load (2 kg for AP 104H5), and the time until it lets go is recorded. Most tests are stopped before the tape fails, so shear is printed as a minimum, such as “> 600 h”.
Shear measures cohesion: resistance to creep under a constant load. It decides whether a mounting or joining tape keeps holding, and it matters even for a removable tape that must not slide off a vertical surface.
What does solids content tell you?
Solids is the part of the adhesive that stays after drying, found by drying a sample at 150 °C for 90 minutes. A higher-solids grade puts down more adhesive for each kilogram bought and leaves less solvent for the coating line’s dryer to remove. Our high-solids grades run at about 64%.
How is viscosity measured?
We measure viscosity on a Brookfield viscometer (RVD11, spindle 5, 10 rpm, 25 °C) and report it in poise; one poise is 100 centipoise. It has to suit the coating head. AP 0132 and AP 0140, at 0.2–1.0 poise, lay down thin lamination coats, while most of our tape grades sit between about 20 and 90 poise. We can make a grade thicker or thinner at the same solids.
How do the numbers work together?
No single number makes a good tape. A few rules of thumb help when you compare grades:
- Adhesion and cohesion pull against each other. Crosslinking raises shear and lowers peel: AP 1765 gives 2500 gf/25 mm peel without hardener and 1700 gf/25 mm with it, while its shear rises to more than 360 hours.
- Removable tapes combine a low peel with a high tack and enough shear to stay put. Permanent and mounting tapes want a high peel and a high shear.
- Peel rises with coat weight up to a point, so a value measured at 25 gsm is not the value at 50 gsm.
- Stainless steel is a high-energy surface. On low-energy plastics such as PE and PP the same adhesive peels lower; choose a grade specified for them, such as AP 3065 or AP 1765.
- Values change as the adhesive cures. Our self-crosslinking datasheet grades reach full cure in up to 24 hours at room temperature once the solvent is removed.
How can you compare grades?
Our product finder plots every catalogue grade on any two of these properties and converts peel, tack and viscosity into the units you work in, from N/25 mm and N/cm to lbf/inch and centipoise. For a shortlist on your own backing and coat weight, ask us for samples and datasheets.