Adhesive selection can be challenging, and it’s even more difficult in applications that generate heat like electronics, batteries, and more where the risk of fire is present. You can find many flame-retardant pressure sensitive adhesives on the market, but flame-retardant doesn’t necessarily mean halogen-free. So, if there are available options, why should you consider choosing a halogen-free tape?
Keep reading to see what classifies an adhesive as halogen-free, why you might consider a halogen-free tape in your next heat-generating application and learn more about some of the many halogen-free tapes available from tesa®.
What Are Halogen-Free Tapes?
Many adhesives in today’s market have unnecessary added halogen chemicals to help applications withstand heat. These chemicals can produce toxic fumes when burned, and when inhaled, put end-users at additional harm.
A halogen-free PSA isn't necessarily (and probably isn't) completely free of halogens, but to be considered “halogen-free” a material must contain less than 900 parts per million (ppm) of chlorine, bromine, iodine, fluorine, or astatine. Additionally, the combined concentration of these chemicals must be less than 1,500 ppm.
Halogen-free tapes offer many similar features and levels of performance as their alternatives, but it’s important to understand the application's needs and environment it will operate in to make the best choice regarding material selection. Halogen-free tapes are an excellent choice for applications where fire safety, environmental impact, or regulations around hazardous substances are a concern.
Why Have Halogens Been Used in Pressure Sensitive Adhesives?
Flame-retardant additives containing halogens have previously been incorporated into many materials to enhance their ability to resist flames, burn slowly, or self-extinguish, which they do well. Chlorine and bromine, for instance, are commonly used in electronics because of their flame-retardant properties. They’re also easy to blend, compatible with electronic components, and relatively cost-effective.
Why Use Halogen-Free PSAs?
Fire-resistant and flame barrier materials provide an additional layer of safety, especially for applications in confined spaces, such as batteries, portable electronics, data centers, aviation, personal vehicles, elevators, and more. If a fire were to break out in these settings, the smoke and fumes given off by the burning material could be just as harmful or worse than the fire itself.
Halogen containing materials can also produce acidic byproducts, which in applications containing metals could be especially detrimental to performance and product life. Halogen-free materials are less concentrated with the compounds that produce these byproducts and offer less risk of corrosion.
When discarded or burned, halogen-free tapes have less impact on the environment. For decades, the electronics industry has faced pressure to use more environmentally friendly materials, driven by initiatives like REACH, RoHS, and other similar regulations. This trend isn’t expected to slow down, so material suppliers like tesa® are ahead of the curve in offering a large variety of halogen-free tapes and adhesives available.
With the increasing presence of electronic devices in everyday life, the demand for flame-resistant materials that meet standards like UL, ULC, FMVSS-302, and others continues to grow.
What Are Some Halogen-Free Tape Alternatives?
tesa® has an impressive catalogue of halogen-free tapes including many that are converted in custom solutions from Marian. While the list below isn't near exhaustive, we've included some key materials offered from our preferred material partner tesa® that can be used in various industries and applications while helping you meet your goals to use halogen-free materials.
- The tesa® flameXtinct series offers foam, filmic, and acrylic core tapes specifically designed as flame-retardant adhesives. This product line is high-performing and can easily be die-cut, making it an excellent choice for applications exposed to high heat.
- tesa® flameXtinct 45001 – PE foam backing – used for permanent bonding in demanding applications
- tesa® flameXtinct 45051 – Filmic backing – used for laminating applications with flame-retardant requirements
- tesa® flameXtinct 45063 & 45065 – Acrylic core backing – used for permanent bonding applications. These adhesives provide good adhesion to a variety of substrates including metal, powder coated surfaces, glass, and more.
tesa® has rigorously tested and confirmed the adhesive properties and flammability of these tapes in accordance with UL94 standards.
2. tesa® 58372 is a leading material in the EV and battery market. This double-sided PET tape is translucent and designed with flame-retardant tackified acrylic adhesive. Along with being halogen-free, this material is UL listed, offers good bonding performance, has high long-term reliability and aging resistance, and more. This material can also be used in other mounting applications and is easily converted for custom applications.
3. tesa® 4965 Original Next Gen is the greener version of the popular tesa® 4965 Original. This double-sided tape provides a reliable bond, even on low-surface energy surfaces. It's a very versatile material and is used in a variety of industries including the medical industry (skin contact certification according to ISO 10993-5 and ISO 10993-10) and is one of Marian's go-to adhesives. tesa® 4965 Original Next Gen is also designed to withstand a number of environmental factors including UV, humidity, and high temperatures and is an excellent material for converted applications.
Key Takeaways
- Flame-retardant and flame-resistant materials aren't necessarily halogen-free
- Halogen-free tapes and other materials are not necessarily completely free of halogen materials
- To be considered halogen-free, a material must contain less than 900 ppm of chlorine, bromine, iodine, fluorine, or astatine or the combined concentration of these chemicals must be less than 1,500 ppm
- Halogens have previously been added to materials to enhance flame resistance, but halogens release toxins into the air when burned
- Materials designated "halogen-free" have less environmental impact, a lower risk of corrosion, and provide additional safety
- tesa® has a vast assortment of halogen-free tape materials outside of the materials highlighted in this post
- Marian can laminate or convert halogen-free materials for custom applications
Why Marian for Your Precision Converted Solutions?
Marian is the leading global converter for your custom applications. With custom converting capabilities like rotary die cutting, laser cutting, water-jet cutting, and access to world-class thin, flexible materials, including halogen-free tapes, from top suppliers all over the world, our teams are ready to help you bring your next application to life!
Marian's unmatched capacity allows us to manufacture billions of converted parts for our customers, no matter where they're located. Housed in our global headquarters, Marian's machine shop is home to a team of mechanical engineers that build converting equipment exclusively for our global locations.
Contact us to talk about your current or upcoming application needs, request a sample or prototype, or to get more details on any of the halogen-free materials discussed (or ask about others).
