Surlyn® Relieves the Pain of Delamination in Foil Packaging

Hisamitsu Pharmaceutical Co. Ltd. uses DuPont™ Surlyn® in foil packaging to prevent delamination caused by the active ingredients in its Salonpas muscle pain relief patch.

With its excellent hot tack strength and low-temperature sealing properties, Surlyn® also helps increase Salonpas packaging line speeds.

The Challenge

Originally, low-density polyethylene (LDPE) was used in the inner foil packaging layer. However, the high levels of camphor and menthol –the active ingredients that make Salonpas so effective –were causing the packaging structure to delaminate, and the foil to corrode. Basically, the active ingredients were permeating through the LDPE sealant layer designed to contain them.

The Solution

Hisamitsu Pharmaceutical’s operation in Vietnam selected Surlyn® ionomer resin to replace the LDPE, due to its exceptional seal integrity. Unlike LDPE, Surlyn® is not impacted by contact with camphor and menthol. It also provides low sealing temperature, better hot tack, and allows for higher line speeds, compared to LDPE.

Key Advantages

The benefits of switching to Surlyn® for Salonpas foil packaging include:

  • Improved seal integrity, with excellent adhesion to foil.
  • Excellent flex crack resistance, which eliminates foil corrosion problems.
  • Increased packaging line speeds.

Foil packaging made with Surlyn® helps maintain the effectiveness of Salonpas medicated patches, used to provide muscle pain relief worldwide.


Because DuPont cannot anticipate or control the many different conditions under which this information and/or product may be used, it does not guarantee the applicability or the accuracy of this information or the suitability of its products in any given situation.