Quality
A sealant is judged twice: on the data sheet before the order, and at the joint two years later. The first is what we can document here. The second is why the methods below matter.
The tests behind the table
| Property | Method | Why it decides the outcome |
|---|---|---|
| Tensile strength | GB/T 528 | Whether the bead itself tears before the bond does |
| Elongation at break | GB/T 528 | How far the joint can move before the sealant fails |
| Tensile shear strength | GB/T 7124 | Load transfer between glass or metal and the bead |
| Shore A hardness | GB/T 531.1 | Soft enough to seal, hard enough not to sag |
| Skin time | GB/T 13477.5 | How long you can tool the bead before it skins |
| Sag resistance | GB/T 13477.6 | Whether the bead stays put on a vertical joint |
| Extrusion rate | GB/T 13477.4 | Gun time per cartridge on a cold morning |
| Density | GB/T 13477.2 | Coverage per kilogram, and therefore cost per metre |
| Volatile content | GB/T 2793 | Shrinkage after cure; solvent content in the drum |
| Cure rate | HG/T 4363 | Hours to handling strength at a given temperature and humidity |
| Elastic recovery | GB/T 13477.13 | Whether the joint closes again after movement |
Typical value vs batch result
Every figure on a model page is a typical value from the printed catalogue. It tells you what the product is designed to do; it does not tell you what is in the drum you receive. For that you need the batch record, and you should ask for it before approving a shipment — tensile, elongation and skin time at minimum.
This distinction is not pedantry. Two batches of the same model can differ by several percent in tensile strength and still be in specification; a customer who specified the typical value as a minimum has bought a problem.
What a batch record contains
The batch record is the only document that describes the material you will actually receive. It is useful only if it carries all six fields below; a certificate with a result but no specification range cannot be accepted or rejected on any rational basis.
| Field | What it ties to |
|---|---|
| Batch number and production date | The drum, the pallet and the shipping documents |
| Test method | The GB/T or HG/T method named on the model page |
| Measured result | The figure for that lot, not the catalogue typical value |
| Specification range | The limits the batch was released against |
| Operator or laboratory | Who ran the test; a subcontracted test names the laboratory |
| Retention sample reference | The stored sample that can be re-tested if a dispute arises |
Traceability and retention
Each batch is recorded against its production date and retained sample, so a complaint about a specific drum can be traced back to the material that was tested rather than to a grade in general. Ask for the retention sample reference with the batch record: it is the difference between a conversation about a number and a conversation about your material.
What this system does not do is turn a typical value into a guarantee. If your specification needs a minimum, write the minimum into the purchase order and require the batch record to meet it; the methodology page explains how to phrase that and what to do when a result falls outside the range.
Documents
Certificate scans are supplied with the quotation package — business licence, ISO 9001 and the product certificate for the model you are buying. Ask for the current set and we will send the documents naming the same legal entity as the invoice.
Quality system
The company works to ISO 9001. The certificate and its scope are available on request — ask for them together with the batch record so both can be checked against the same legal entity.