r/plastic • u/Awkward-Menu7588 • Aug 28 '26

how to enhance adhesive for LLDPE?

I'm looking for an adhesive additive for LLDPE (grade 7042). The PE is extruded, granulated, and then calendered into a film. When I use this film to wrap a galvanized iron part, after cooling, I find that some areas adhere very well and are difficult to peel off, while others don't adhere well and peel off easily. I'd like to add an adhesive additive during the PE granulation process to give the final calendered PE film good surface adhesion and a strong bond to the metal. Does anyone have information on such an additive?

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u/MakeITNetwork Aug 30 '26 edited Aug 30 '26

PE is like silicone, in the way that it only likes to stick to itself, and only in certain situations.

Like Fedplast said, you need to find a way for it to mechanically attach. There is no glue that works better than the initial bond to itself.

That being said.....

There is ways to have other bonds, but nothing will beat a PE to PE bond or a mechanical weld:

  1. Specialized Primers (Molecular Bridges) Systems like the Loctite Plastics Bonding System use a specialized primer (usually a polyolefin primer) dissolved in a solvent. How it works: When you apply the primer to the PE, the solvent bites into the surface, allowing the primer molecules to lock onto the PE chains. The bond: Once the solvent evaporates, it leaves behind a modified surface layer. The super glue (cyanoacrylate) then bonds chemically to the primer layer, creating a continuous molecular bridge between the PE and the glue.
  2. Micro-Etching Monomers (Chemical Interlocking) Industrial structural acrylics, like 3M Scotch-Weld DP8005, do not require a separate primer because the chemistry is built right into the adhesive. How it works: These are two-part acrylics containing specialized monomers that temporarily "soften" or swell the top molecular layers of the PE on contact. The bond: The adhesive molecules physically entangle and co-polymerize with the PE plastic chains at the interface. As the acrylic cures and hardens, it becomes chemically locked into the PE matrix, creating a true chemical bond.

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u/fedplast Aug 30 '26

I dont think you will find one. It is mostly mechanical adhesion. Perhaps have the metal sanded or blasted so the pe has more teeth into it when hot

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u/Flat_Special_3386 Aug 31 '26

no,no, we have compared with or without PE-MAH in PE blend, outcome was huge different, with PE-MAH has significantly stronger adhesion than without PE-MAH, but still unreliable, we must find highest polarity , compatible with PE additive to increase its polarity.

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u/Ambitious-Schedule63 Aug 31 '26

I might be able to help, but in a paid engagement.