Polyurethane (PU) is a versatile material with a wide range of applications as we forementioned at Part 1: The Ultimate Guide of PU Leather: From Manufacturing to Application, from furniture to footwear and everything in between. In our quest to understand PU better, we'll explore two important categories: solvent-based PU and non-solvent PU. But beyond their applications, let's delve into the critical factors of human health and environmental impact.


How can Solvent & Non-solvent PU affect human health?

Solvent-based PU (Polyurethane) products can potentially affect human health in several ways due to the presence of volatile organic compounds (VOCs) and other chemicals. Here are some ways in which solvent-based PU can impact health:

  • VOC Emissions: Solvent-based PU products often release VOCs into the air. These VOCs can contribute to indoor air pollution, leading to symptoms such as headaches, dizziness, eye and throat irritation, and respiratory problems. Prolonged exposure to high levels of VOCs can be more harmful.
  • Allergic Reactions: Some individuals may be sensitive or allergic to certain chemicals used in solvent-based PU production. Contact with PU materials can lead to skin rashes, itching, or allergic dermatitis.
  • Respiratory Issues: Inhaling VOCs emitted from solvent-based PU can irritate the respiratory system. It may exacerbate symptoms in individuals with asthma or other pre-existing respiratory conditions.
  • Toxic Chemicals: The production of solvent-based PU involves the use of isocyanates, which are known to be toxic. Prolonged exposure to isocyanates, especially in industrial settings with inadequate safety measures, can lead to severe health issues, including lung damage and asthma.
  • Fire Hazards: Some solvent-based PU materials may be flammable, and exposure to fire or high heat can release toxic gases and chemicals, posing fire hazards and health risks.

To mitigate the potential health risks associated with solvent-based PU products, it's important to use them in well-ventilated areas to reduce indoor air pollution. In industrial settings, proper safety measures and personal protective equipment should be employed when working with these materials. Additionally, selecting low-VOC or water-based PU products can help minimize health and environmental impacts.

It's crucial to follow safety guidelines provided by manufacturers when using PU products and to seek medical attention if any adverse health effects are experienced.


Non-solvent Polyurethane (PU), often referred to as water-based PU, generally has a lower impact on human health compared to solvent-based PU. Here's how non-solvent PU can affect human health differently:

  • Lower Volatile Organic Compounds (VOCs): Non-solvent PU contains significantly fewer Volatile Organic Compounds (VOCs) compared to solvent-based PU. VOCs can contribute to indoor air pollution and have been associated with various health issues, including respiratory problems, eye irritation, and headaches. Using non-solvent PU products indoors results in improved indoor air quality and reduced health risks.
  • Reduced Inhalation Exposure: Since non-solvent PU has lower VOC emissions, workers involved in its production and application are less exposed to harmful airborne chemicals. This can lead to a safer working environment and fewer cases of occupational exposure-related health problems.
  • Lower Risk of Skin and Eye Irritation: Non-solvent PU is generally safer for direct skin contact. It is less likely to cause skin irritation or allergic reactions compared to solvent-based PU, which often contains harsh solvents that can be harmful to the skin. Workers handling non-solvent PU are at a reduced risk of dermatological issues.
  • Reduced Toxicity: Non-solvent PU formulations typically use fewer toxic chemicals in their production. This reduces the potential for acute or chronic health effects, especially when there is accidental exposure
  • Less Harmful Off-Gassing: Non-solvent PU products emit fewer toxic fumes when they are used indoors. This is particularly important in enclosed spaces, as it reduces the risk of respiratory discomfort and long-term health problems associated with indoor air pollution.
  • Improved Occupational Safety: Workers involved in the production and application of non-solvent PU face fewer health risks compared to those working with solvent-based PU. Occupational safety is generally enhanced when using water-based PU products.

It's important to note that while non-solvent PU is considered safer for human health, proper safety precautions, including the use of personal protective equipment (PPE), good ventilation, and adherence to safety guidelines, should still be followed when handling any chemical products. Additionally, individuals with specific sensitivities or allergies should exercise caution and consult with professionals before prolonged exposure to any PU product.


How can Solvent & Non-solvent PU affect the environment?

Solvent-based Polyurethane (PU) coatings and products can have several adverse effects on the environment due to the release of volatile organic compounds (VOCs) and other chemicals. Here are some ways in which solvent-based PU can impact the environment:

  • Air Pollution: The most significant environmental impact of solvent-based PU is air pollution. During the application and drying process, these products release VOCs into the atmosphere. VOCs can react with other air pollutants and sunlight to form ground-level ozone, which is a major component of smog. Ground-level ozone can harm human health and damage vegetation.
  • Water Pollution: When solvent-based PU is cleaned or disposed of improperly, it can contaminate water sources. VOCs can evaporate into the air, while runoff can carry PU residues into rivers, lakes, and groundwater. This contamination can harm aquatic life and disrupt ecosystems.
  • Toxic Chemicals: The production and disposal of solvent-based PU involve the use and release of toxic chemicals. For example, the manufacturing process may use isocyanates, which are hazardous substances. Improper disposal of PU products can introduce these toxins into the environment.
  • Hazardous Waste: Solvent-based PU products can generate hazardous waste during production, application, and disposal. Proper handling and disposal of this waste are essential to prevent environmental contamination.
  • Resource Depletion: The production of solvent-based PU relies on the use of non-renewable fossil fuels and chemicals, contributing to resource depletion. This includes the extraction and processing of raw materials, such as petroleum-based solvents.
  • Global Warming: VOCs released during the production and use of solvent-based PU products can contribute to climate change. Some VOCs are greenhouse gases that trap heat in the atmosphere, leading to global warming.

To mitigate the environmental impact of solvent-based PU, there is a growing trend toward the use of water-based PU coatings, which contain fewer VOCs and are less harmful to both human health and the environment. Additionally, proper waste disposal and recycling practices can help reduce the negative effects of solvent-based PU on the environment.


Non-solvent Polyurethane (PU), often referred to as water-based PU, generally has a lower environmental impact compared to solvent-based PU. Here's how non-solvent PU can affect the environment differently:

  • Lower VOC Emissions: One of the primary advantages of non-solvent PU is that it contains significantly fewer Volatile Organic Compounds (VOCs). VOCs are a major contributor to air pollution and the formation of ground-level ozone, which can be harmful to human health and the environment. Non-solvent PU emits fewer VOCs during application and drying, reducing its impact on air quality.
  • Reduced Air Pollution: With lower VOC emissions, non-solvent PU coatings and products contribute less to smog formation and respiratory problems. This makes them a more environmentally friendly choice, especially in regions with strict air quality regulations.
  • Water-Based Formulation: Non-solvent PU is based on water as a carrier, rather than organic solvents. This means that it can be diluted and cleaned up with water, reducing the risk of water pollution. It also makes disposal and handling less hazardous to the environment.
  • Less Toxic Chemicals: Non-solvent PU formulations typically use fewer toxic chemicals in their production. This reduces the potential for harm to ecosystems when PU products reach the end of their lifecycle and enter the environment.
  • Resource Efficiency: The production of non-solvent PU often requires fewer non-renewable resources compared to solvent-based PU. This can include a reduction in the use of petroleum-based solvents and chemicals.
  • Reduced Global Warming Potential: While both solvent-based and non-solvent PU can contribute to global warming through the release of VOCs, non-solvent PU usually has a lower global warming potential due to its reduced VOC content.
  • Energy Efficiency: Non-solvent PU formulations can be more energy-efficient during the manufacturing process since they don't require the use of high-temperature ovens to evaporate solvents.


It's important to note that the environmental impact of PU products also depends on factors such as production practices, disposal methods, and the specific ingredients used. While non-solvent PU is generally considered more environmentally friendly, responsible manufacturing, usage, and disposal practices are essential to minimize the overall impact of any PU product on the environment.


In conclusion, the choice between solvent-based and non-solvent PU involves careful consideration of your specific needs and environmental responsibilities. As consumers become more conscious of health and sustainability, non-solvent PU is likely to play a more prominent role in the future of PU applications. It's a reminder that innovations in materials science continue to evolve, not only to meet our demands but also to safeguard our health and the planet.