China's light industry standards for zippers are organised by construction rather than by end use, and that structure explains most of the confusion foreign buyers meet when a Chinese factory quotes "QB/T" compliance. There are three core product standards, one for metal zippers, one for injection-moulded plastic zippers and one for nylon coil zippers. Each defines its own classification, dimensions, performance requirements and test methods.

This article explains what each standard covers, how the requirements are structured, what a compliant test report looks like, and how an export buyer should layer these standards with the European or American requirements that the garment will eventually face.

1. Scope: three standards, three constructions

The three standards divide the market by how the teeth are made, because the manufacturing process determines the defects and the failure modes.

  • The metal zipper standard covers zippers with metal teeth formed from wire or strip, usually brass, aluminium or zinc alloy, with metal or plastic sliders.
  • The injection-moulded standard covers zippers where the teeth are moulded directly onto the tape from a thermoplastic compound, commonly polyacetal, sometimes with a moulded or metal slider.
  • The nylon coil standard covers zippers where a continuous monofilament coil is woven or sewn onto the tape, with a slider that separates and re-engages the coils.

Each standard applies to zippers made and sold in China, and each is widely referenced in export contracts because the factory's quality system is built around it. A factory that says it "meets the national standard" is usually referring to one of these three, and the buyer should ask which one and which edition.

2. Key requirements

Although the three documents differ in detail, their requirement structure is similar.

Classification and designation. Zippers are classified by construction, by size number, and in some cases by grade or end use. The size number relates to the chain dimensions, and it is not interchangeable with the size numbers used in European or American practice without checking the dimensional table.

Appearance and workmanship. Requirements cover tape defects, weaving and dyeing faults, tooth alignment, plating appearance, moulding flash, slider finish and the cleanliness of the assembly. These are assessed against a limit sample and a defect definition, so the standard is only useful if a limit sample exists.

Dimensions. Tape width, chain width, thickness, and length tolerance for the finished zipper, including the effect of the end treatment.

Mechanical performance. Chain strength, slider pull-off, stop retention, slider lock, puller attachment and resistance to separation, each tested by the method in the relevant standard.

Durability. Reciprocating cycling of the slider, with acceptance based on function after the specified number of cycles.

Colourfastness. Fastness of the dyed tape to washing, rubbing and perspiration, which matters more than buyers expect for garment-dyed and washed programmes.

Corrosion. Salt spray or equivalent for metal components, with acceptance based on appearance and function.

Safety and labelling. Textile safety requirements for the tape, marking of the product and packing requirements are referenced, and the applicable textile safety code applies to the tape as a textile product.

The numeric limits sit in tables in each standard and vary by size and grade. They should be read from the current edition rather than carried over from an older report, because the editions have been revised.

3. Test methods

The methods are defined within each standard and are broadly comparable with the methods used internationally, but they are not identical. A test report should therefore state the standard, the clause and the specimen details.

  1. Specimens are taken from finished production zippers, in each size and colour being supplied.
  2. They are conditioned in the standard atmosphere specified for textile testing before the mechanical tests.
  3. Mechanical tests are run on a tensile machine with fixtures suited to the property, and the maximum force and failure mode are recorded.
  4. Cycling tests are run on a reciprocating rig, and the zipper is assessed for function at the end of the run and at intermediate intervals if the method requires it.
  5. Colourfastness and corrosion tests follow the method named in the standard, with the exposure conditions recorded.

The most useful reports go beyond pass or fail: they give the measured value, the requirement, and the failure mode. That is what allows a buyer to compare two suppliers or two constructions on the same basis.

4. Common non-conformities

  • The size number on the label does not match the measured chain dimensions, usually because two size systems have been mixed.
  • Moulding defects on injection-moulded teeth, such as flash or short shots, that are visible but not caught because no limit sample was agreed.
  • Colourfastness failures on dyed tape after washing, particularly in dark shades and in tape from a subcontract dyehouse.
  • Salt spray failures on plated sliders, often a plating thickness or passivation issue.
  • The standard and edition are not stated on the certificate, so the requirement cannot be verified.
  • A shipment mixes constructions, for example metal and nylon, under a single certificate issued against one standard.
  • Puller attachment tested as slider pull-off, which reports a stronger number than the property that actually matters.

5. Practical sourcing advice

Match the standard to the construction. Asking for the metal zipper standard on a nylon coil product tells the factory that the specification was copied, and it invites a certificate that does not describe the goods.

Ask for the edition, the grade and the test report together, and check that the report's specimen description matches the purchase order: size, tape composition, finish and colour. Where the buyer needs a specific performance level, write the property and the limit into the purchase order rather than relying on the standard's default table.

For export programmes, treat these standards as the manufacturing baseline and layer the destination requirements on top. A zipper that meets the Chinese product standard still has to pass the European restriction tests, the American children's product rules where applicable, and the customer's own restricted substances list. The Chinese standard gives a sound dimensional and durability baseline; it is not a substitute for destination compliance.

Finally, build a limit sample library. Appearance requirements in any standard are only enforceable against an agreed reference, and a photographed limit sample signed by both parties prevents most of the arguments that arise at final inspection. Where a table or clause is ambiguous, refer to the standard text and ask the factory to quote the clause it is working to.