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changeHot melt adhesive granulesSuppliers, even if they claim that the parameters are exactly the same and can be directly replaced, must still make new samples on their own equipment and actual substrates. The reason is that two adhesives with the same nominal softening point of 85 ℃ may have completely different resin sources, thickening systems, and additive ratios, as well as differences in melt viscosity, opening time, and initial viscosity curves. Directly entering the mass production line carries extremely high risks.

| test item | method | Qualification Standard |
|---|---|---|
| bond strength | Pull and pull the finished product according to the official parameters | The damaged surface is on the paper fiber, not the entire adhesive layer falling off |
| Aging stability | Leave at room temperature for 24-72 hours | No glue, no cracks on the spine of the book |
| heat resistance | Leave it at high and low temperatures for several hours each | High temperature does not stick back, low temperature does not brittle off |
| Performance on the computer | Run 100 items continuously | No wire drawing, no nozzle blockage, stable glue dispensing |
First, request the testing report and brand process card, then conduct the above four tests on a small sample. After passing, a small batch of trial production will be carried out for one order. Only when it is stable will the full quantity be switched, and the old rubber inventory will be retained as a transition. When switching, be sure to empty the glue tank and avoid mixing old and new. Sunlife hot melt adhesive provides free sample shipping and on-site adhesive testing support for new customers. Guangzhou Sunlife Trading will first understand your existing brand parameters and equipment models, and provide corresponding alternative solutions to reduce switching risks.
The common motivation for changing suppliers is to save money, but the real comparison is the “cost per piece of glue”. Some cheap materials have high melting viscosity and require an increase in the amount of glue applied, resulting in a 10% decrease in unit price and a 20% increase in usage, which actually makes them more expensive; Including rework and downtime losses, the gap will be even more pronounced. When making a sample, it is important to record the amount of glue consumed per piece and include it in the comparison table along with the unit price, so that the conclusion can stand firm.
Q1: Do we need to make samples even if the same supplier changes batch numbers?
It is not necessary to provide a complete set, but it is recommended to perform first piece pull confirmation as there is minimal fluctuation between batches from reputable suppliers.
Q2: How long does it usually take to make a sample?
Sending samples takes 1-3 days, testing on the machine takes half a day, and aging observation usually takes 3-5 days to draw conclusions.
Q3: Can new glue be poured directly into unused old glue?
Not recommended, compatibility is unknown and prone to delamination. New glue should be applied after cleaning the cylinder.
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