1. Chemical composition and toxicity risk
The main raw materials of polyurethane adhesives are polyisocyanates and polyols. The core safety risk lies in the incompletely reacted free cyanate ester monomers (such as TDI, MDI). These substances are highly irritating and can cause harm to the human body through inhalation or skin contact. Long-term or high-concentration exposure may damage the respiratory tract, trigger asthma and even more serious lung problems. In addition, some formulas may contain solvents (such as acetone, ethyl acetate) or additives, which may be flammable, emit volatile organic compounds (VOCs), or have certain toxicity.
2. Safety of the curing process
Polyurethane adhesives carry the highest risk before curing. The harmful monomers or solvents of adhesives in liquid state are the most volatile. Therefore, forced ventilation in the construction environment is of vital importance. Operators must wear personal protective equipment, such as chemical-resistant gloves, goggles and appropriate gas masks, to prevent inhalation and skin contact. One-component moisture-curing adhesives will react with moisture in the air to release carbon dioxide, which may accumulate in a confined space. Ventilation should also be noted.
3. Long-term safety after curing
Once fully cured, the
Polyurethane Adhesive will cross-link into a stable high-molecular polymer, effectively fixing the harmful substances inside, and greatly reducing its volatility and migration. Therefore, the cured products (such as composite boards and automotive parts) are generally regarded as safe in daily use and pose extremely low risks to consumers. The safety of its final products has been strictly controlled through regulations and standards.
4. Environmental and ecological safety
From the perspective of life cycle assessment, the environmental impact of polyurethane adhesives is mainly reflected in the production process and the waste disposal stage. The emission of harmful substances needs to be controlled during the production process. Discarded adhesives, as chemical waste, should not be discarded at will, especially those containing heavy metal catalysts. They need to be handed over to professional institutions for treatment to prevent pollution to soil and water bodies.
Summary
The safety of polyurethane adhesives is dual. During the production and use (before curing) stage, it is a chemical that requires strict management and poses clear health risks. After complete curing, its products are usually stable and safe. Therefore, the key to safety lies in the standardized management of the production, transportation and construction processes as well as the adequate protection of the operators.
