What should I do if the hot melt adhesive particles stick to the gold and silver cardboard and lose powder? 3 reasons+corresponding solutions

First of all, the conclusion is that the powder on gold and silver cardboards is mostly due to “surface coating not being treated properly” or “glue temperature not being pressed down”

Gold and silver cardstock is coated with a layer of gold and silver foil or PET aluminum plated film on the surface of the cardstock. However, when the adhesive is applied, it “powders, delaminates, and peels off”. Usually, it is not due to the poor quality of the adhesive particles themselves, but rather due to low surface energy, weak bonding between the coating and the paper substrate, low adhesive temperature, or mismatched opening time. As long as we start with the selection of glue, surface treatment, and process, powder loss can be basically solved.

Reason 1: The surface of the gold and silver cardboard is too slippery, and the glue cannot penetrate

The aluminum plating layer hardly absorbs adhesive, and ordinary adhesive particles only “float” on the surface when applied. The solution is to first gently wipe off the release agent with alcohol, or perform slight polishing or plasma treatment before pasting the box to improve surface energy; Choose a type of adhesive with good adhesion to the coating and laminating materials.

Reason 2: Insufficient adhesive temperature, failure to “weld” the coating to the paper substrate

Gold and silver cardboard has slow thermal conductivity and a slightly higher adhesive temperature of 5-10 ℃ compared to ordinary cardboard. The temperature is not enough, the glue cools down before it even wets, and the powder falls off with a gentle pull. Suggest raising the working temperature to 180-190 ℃ and extending the pressing time appropriately.

Reason 3: Inaccurate opening hours

The interval between gluing and pressing is too long, and the surface of the glue has already formed a crust, which cannot be firmly adhered even after pressing. The sealing line should be adjusted to increase the initial adhesion and shorten the open window to achieve “pressing after coating”.

FAQ

Q: Can we use the same adhesive for all gold and silver cardboards?
Answer: It’s not possible. There is a significant difference between full plate hot stamping and partial hot stamping, PET aluminum plating, and aluminum foil paper. It is best to provide a sample for the supplier to make a small sample for confirmation.

Q: Can the box with fallen powder be reworked?
Answer: If the coating has been damaged, it is difficult to save. If there is a slight opening of the adhesive, it can be repaired by applying heavy pressure; For batch issues, it is recommended to replace the adhesive and redo it to avoid customer complaints at the end.

Q: Is there a ready-made solution?
Answer: Guangzhou Sunlife TradingSunlifehot melt adhesiveThere is a packaging and sealing series specifically designed for laminated and aluminum coated cardboard, with adjustable opening time. The adhesion of gold and silver cardboard is tested to be stable, and small batches can apply for sample testing first.

In one sentence: If gold and silver cardboard loses powder, first check the surface treatment and glue temperature, choose the right high adhesion glue, raise the temperature a few degrees, and shorten the open window. Most problems can be solved on site.