Humans have been using adhesives for centuries. From early birch to bitumen glues, and animal collagen, adhesives have been known in many civilizations including Ancient Egypt, Roman, and Greeks. Synthetic polymers were introduced in the early 20th century. These were game-changing for our industries. From woodworking to bookbinding, and bottle labeling to the folding carton, adhesives are used in every sector today.
Hot melt adhesives (HMA) derived from polymer-based thermoplastics are extensively used. The demand for the product is expected to rise with rising awareness of its superiority over water based adhesives. Increased demand for packaging solutions, as global industrial activity recovers from the pandemic, will further push the market size higher. By 2027, the global hot melt adhesives market is expected to reach a size of $11.4 billion, growing at a CAGR OF 4.8% between 2022 and 2027.
Image Source: https://www.grandviewresearch.com/industry-analysis/hot-melt-adhesives-market
EVA Hotmelts and Metallocene Hotmelts
Hot melts can be unsuitable in particular environments. You need to make informed decisions when you are using HMAs for industrial use. A lot depends on the materials you are working with. There are two common types of hotmelt adhesives: Ethylene Vinyl Acetate (EVA) and metallocene. Both of them have their unique advantages.
It is a copolymer adhesive, used in our industries like paper, packaging, Folding Carton, and more. Some desirable features of this product are strong mechanical strength, and paraffin solubility, along with excellent adhesion. The EVA segment occupied more than 40% volume share in the US market in 2020.
EVA also bonds to a broad range of surfaces. They show excellent ability to penetrate difficult coatings like wax or adheres to the surface of metalized PET. EVA’s can be formulated to have good resistant to cold or hot temperatures
With high temperatures, any organic material tends to char. EVA will char more readily than metallocene even if they are protected by anti-oxidizing agents. At some point, charring conditions reach such levels, that nozzle, hoses, and other parts of the application system need replacing.
Metallocene adhesives are a recent innovation in polyolefin technology. It offers increased efficiencies in industrial applications.
One advantage of metallocenes adhesives is that they are lower in density than EVA hotmelts. You can use them for excellent adhesive strength, even when used in very small quantities. Using less material leads to higher mileage, which means better cost optimization. Moreover, they show better stability than EVA hotmelts in all temperature conditions. With great cold and hot climate resistance, metallocene hotmelts can decrease your product returns and pop-opens.
Maintenance expenses can further be avoided as metallocene products have better pot stability This means your nozzles will need less maintenance. Other advantages include low odor, which improves workplace air conditions.
Image Source: https://www.afera.com/uploads/Bestanden/Hot%20Melt%20Market%20Report%20Article%20September%202017.pdf
Which to Choose
The recent VAM shortages have increased the cost of EVA’s when compared with Metallocene. Keep in mind that Metallocene’s will be more cost effective because of their lower density and better mileage.