Hot glue sticks are ubiquitous in crafting, household repairs, and industrial applications due to their ease of use and strong, quick-setting bond. Understanding the environmental impact of this widely used product requires examining its chemical makeup and how it interacts with natural biological systems. The true environmental fate of standard hot glue is determined by its ability to be processed by natural biological systems.
The Chemical Composition of Standard Hot Glue
The vast majority of standard hot glue sticks are made from a synthetic polymer called ethylene-vinyl acetate, or EVA copolymer. This material is a thermoplastic, meaning it melts when heated and solidifies upon cooling, which is the mechanism that allows a hot glue gun to function. The EVA copolymer itself is a petroleum-derived plastic, similar to polyethylene, built from long chains of repeating molecular units.
The EVA component, which provides the strength and flexibility of the adhesive, makes up between 30% and 50% of the total formulation. To adjust the glue’s properties, manufacturers blend the EVA with other additives, primarily tackifying resins and wax. These components are all synthetic and contribute to the overall resistance of the glue to environmental breakdown.
Defining Biodegradation and Degradation
The term “degradation” refers to any process that breaks down a material into smaller pieces, which can be caused by physical forces like UV light or mechanical abrasion. Standard plastics, including EVA, do degrade when exposed to the elements, but this process results in the formation of microplastics. These microscopic fragments persist in the environment and are simply smaller versions of the original synthetic material.
In contrast, “biodegradation” is a specific type of degradation that requires the action of naturally occurring microorganisms, such as bacteria and fungi. For a material to be truly biodegradable, these microbes must completely break down the material’s chemical structure and metabolize its carbon. The final products of ultimate biodegradation are simple, natural substances like carbon dioxide, water, and new biomass.
The Environmental Fate of Standard Hot Glue
Based on its composition and the definition of the term, standard EVA-based hot glue is not considered biodegradable. The long, complex molecular chains of the synthetic EVA copolymer are not easily recognized or processed by the enzymes of common soil or marine microbes. Because the material lacks the chemical structures that microbes can easily cleave, it resists assimilation into the natural carbon cycle.
When hot glue is discarded, it does not disappear; instead, it undergoes slow physical degradation. Over many decades, sunlight, heat, and mechanical forces cause the material to fragment into increasingly smaller pieces. This fragmentation is the source of secondary microplastics, which can remain in the environment for hundreds of years.
Eco-Friendly Alternatives and Recommended Disposal
Since standard hot glue is not recyclable and persists indefinitely, the recommended disposal for small household amounts of cured glue is the general waste stream, which leads to a landfill. It is important to prevent hot glue waste from entering soil or waterways, where it can contribute to microplastic pollution.
Consumers seeking more sustainable options can explore alternatives made from natural polymers, which are often marketed as compostable or biodegradable. These products are typically formulated using plant-derived materials such as starch, natural resins, or proteins. Some alternatives have achieved certification, confirming they will break down into natural components under industrial composting conditions. While these eco-friendly glues may have limitations in strength or cost compared to traditional EVA, they offer a viable option for reducing environmental impact in crafting and packaging applications.