Is the PET plastic film firmly adhered by hot melt adhesive particles? Choose the right formula to bond firmly without delamination

The root cause of difficulty in sticking PET plastic film

PET (polyethylene terephthalate) plastic film has low surface energy and high crystallinity, and is widely recognized as a difficult to stick material. Ordinary EVAhot melt adhesive pelletsThe problem of initially sticking PET but suddenly decreasing peel strength after cooling is often encountered, and the fundamental reason is that the adhesive cannot effectively infiltrate the surface of PET.

The key to making the hot melt adhesive particles stick firmly to the PET film is not about “how thick to apply”, but about “choosing the right model”. There is a modified formula specifically developed for low surface energy materials in Sunlife hot melt adhesive granules, which enhances the affinity for PET surface by introducing polar groups. After cooling, the peel strength can reach over 3N/cm.

Selection and operation points

• Choose modified formulaOrdinary packaging EVA adhesive particles with PET peel strength are usually<1N/cm，需选PET专用型或含增粘树脂的改性配方。
• Raise the adhesive temperatureRaising the adhesive temperature by 10-15 ℃ can improve wetting, but not exceeding 180 ℃ to prevent oxidation of the adhesive film.
• Cooperate with corona treatmentIf conditions permit, corona treatment on the PET surface can increase the surface energy to above 42mN/m and double the bonding effect.

The technical team of Guangzhou Sunlife Trading can recommend corresponding models based on customers’ specific PET film types (transparent/aluminum plated/printed surface).

Frequently Asked Questions (FAQ)

Q: How long does it take for the hot melt adhesive particles to peel off after sticking PET?

A: Ordinary rubber particles usually have edge warping within 24-48 hours; After selecting the right modified formula, it can maintain adhesion for a long time without detachment at room temperature.

Q: Can we compensate for the weak adhesion by increasing the amount of glue applied?

A: Not recommended. Excessive thickness of the adhesive layer can increase internal stress and accelerate delamination. The correct approach is to change the formula rather than the amount of adhesive stacked.

Q: Is aluminum coated PET film harder to stick than transparent PET?

A: Yes, it is. The aluminum plating layer blocks the penetration of the adhesive solution, so it is necessary to choose modified adhesive particles with stronger permeability or apply a primer treatment on the aluminum plating surface.