01
Start with the layer, not the material
“Carded thermal bond” still describes thousands of different webs. A supplier can only design the right one when it knows where the web sits: a filter scrim, a diaper acquisition layer, a headliner substrate, a separation geotextile.
Name the layer and its job first. Fiber, basis weight, and the thermal bond follow from that. Say whether the roll should be laminated.
02
Give targets with tolerances
Basis weight, thickness, tensile, and air permeability should each come with a target and an acceptable range. A target with no tolerance cannot be released, and a tolerance with no method cannot be measured.
03
Name the test method
The same property can read differently under different methods. Name the standard — for example ISO 9073-3 for tensile or ASTM D737 for air permeability — and any conditions that matter, such as specimen size or test pressure.
04
Describe the roll
Slit width, core diameter, roll diameter or length, splice allowance, and packaging are part of the specification. A perfect web on the wrong core is still a line stop.
05
Say what the finished good is bought against
If the finished product must meet a filter rating, a geotextile table, or FMVSS 302, say so. Syntex does not certify the finished good, and it designs a better carded web when it knows the target.