Q: Which QB/T 2171 tests apply to nylon coil zippers?
QB/T 2171 is the Chinese light-industry standard for nylon coil zippers, and it sets both dimensional requirements and performance tests. The dimensional side covers tape width, coil width, thickness and length tolerance; the performance side covers pull strength, holding strength of the stops, reciprocating life and colourfastness of the dyed tape. Appearance requirements cover weaving defects, staining and colour evenness.
Testing follows the methods referenced in the standard, with defined sample lengths, clamping and speeds for each test. Reciprocating life is run to a stated number of cycles and the zipper is then checked for tooth deformation, slider function and separation. Colourfastness is assessed against the grey scale. Because the values differ by size and type, take the acceptance table from the standard rather than from a general rule, and refer to the standard text for the test conditions. The same structure carries into QB/T 2172 for injection-moulded plastic zippers, which sets its own size ranges and strength values.
For incoming inspection, sample each lot and each colour, record size, length and lot, and judge against the standard's table. Keep the test report with the shipment so a dispute can be settled on evidence rather than on opinion.