Plastic outgassing and its impacts are well-documented and have been discussed in the industrial world for a long time. Outgassing is a crucial factor for plastic components that are used in high-heat environments, vacuum applications, or enclosed spaces.

What is Outgassing?

Outgassing is the release of gas that was dissolved, trapped, frozen, or absorbed in any material. In the case of advertising signs, when the thermoplastic substrate is exposed to sunlight or heat, trapped gases will be released as part of the outgassing process.

Most plastics contain Volatile Organic Compounds (VOCs) and they are poisonous, carbon-containing chemicals that are volatile enough to evaporate even at room temperature. The water inside the plastic spread on the surface and pump away, making these plastics a source of outgassing for some time.

Advertising Signs & the Bubbling Issue

The most common complaint we hear from our customers is the bubbling (blistering) of vinyl when mounted onto Acrylic, Polycarbonate or painted walls. Since outgassing is a gradual escape of gas, when self-adhesive vinyl is applied onto Acrylic, PC or painted walls, it does not immediately blister. After 2-3 hours of applying the vinyl, or sometimes later, the blisters or bubbles become visible.

When ordinary self-adhesive materials are applied to thermoplastic substrates, outgassing can create bubbles and cause total delamination of the applied label or graphic.

Ordinary labels lift and bubble due to outgassing from PMMA or PC (above), whereas a label stock boasting high permeability (below) does not have this issue.

Many industries use molded and formed plastic panels for demanding engineered applications, and often these are manufactured from materials such as vinyl, acrylics and polycarbonate. However, the impact of environmental factors on these plastics – including exposure to sunlight and high temperatures – can accelerate outgassing.

How to Counteract Outgassing

1st Step - Pre-heating and Pre-drying of Plastics

Depending on the storage and climate conditions, these plastics absorb moisture. Although this can be disregarded for normal application temperatures, it may cause bubble formation during heating when plastics are exposed to higher temperatures. Hence, prolonged pre-drying at temperatures below the softening point of the material is highly recommended. The time and temperature of preheating required to minimize outgassing are determined by the properties of the material used.

2nd Step – Comprehending the Surface

By comprehending the surface of the sign and the type of film used in the graphics, you can avoid these problems, thus ensuring the sign is visually appealing, long-lasting and passes the intended message.

You need to analyze the surface or the thermoplastic substrates used. If the surface is old, then there is a fair chance that any outgassing has finished. Even painted surfaces may cause issues, particularly when using water-based paints.

Conclusion

Even though plastic outgassing cannot be completely prevented, we can reduce the level of it significantly. Since plastics have different outgassing rates, in applications, the choice of the material would be made after thorough tests and comparison of all the material properties, including mechanical strength, ease of manufacture, and electrical breakdown strength in the vacuum.

At Blue Rhine, we stock a wide range of commercially available engineering plastics in sheet, rod, tube and film forms. We can help you determine which plastic is right for your application as our experts have right the tools and expertise to deliver dependable solutions.

Being the best plastic sheet supplier in Dubai, we offer premium acrylic and polycarbonate sheets in the UAE and other GCC countries, including Oman, Saudi Arabia, Kuwait, Qatar and Bahrain. We provide a complete portfolio of acrylic, polycarbonate and vinyl products that are ideal for all your project needs.