Benzene-free PU Adhesive: A Green New Choice for Footwear Bonding

I.       What is Benzene-free PU adhesive?

    Benzene-free PU adhesive refers to a polyurethane adhesive that does not contain toxic aromatic hydrocarbon solvents such as benzene, toluene, or xylene during its preparation and application. It typically uses environmentally friendly solvents or water as the medium, allowing workers to avoid exposure to the pungent odor of benzene-based compounds during production. Additionally, consumers are protected from residual benzene-based solvents in finished footwear, thereby fundamentally eliminating the health hazards posed by benzene-based substances to humans and their pollution to the environment.

II.     How is the performance of Benzene-free PU adhesive?

    Benzene-free PU adhesive perfectly inherits the excellent properties of PU materials, such as high bonding strength, good flexibility, low-temperature resistance, wear resistance, and hydrolysis resistance. Whether bonding materials used in footwear—such as leather, fabrics, various rubbers, or EVA foam materials—or adhering different materials to each other, Benzene-free PU adhesive can form a strong, flexible, and durable bonding layer. The adhesive film it creates can adapt to frequent bending, twisting, and changes in environmental temperature and humidity during shoe wear, ensuring that the sole and upper remain firmly bonded over the long term without delamination. This significantly enhances the overall quality and service life of footwear.

III.   How to use Benzene-free PU adhesive?

    The typical process for using Benzene-free PU adhesive is as follows, although some specialized products may require specific handling:

    1.    Surface Treatment: Perform necessary cleaning, sanding, or chemical treatment on the materials to be bonded to remove oil, plasticizers, etc., ensuring optimal surface conditions.

    2.    Adhesive Application: Apply a uniform layer of adhesive to both surfaces requiring bonding, typically using methods such as brushing, spraying, or roller coating.

    3.    Drying: Place the coated components into a drying tunnel and dry them at a set temperature to allow solvents or moisture to evaporate, bringing the adhesive layer to a tack-free state.

    4.    Activation and Bonding: After the components cool, briefly heat the adhesive layer in thermal activation equipment to restore its tackiness. Then, promptly align the shoe upper and sole and press them together under pressure.

    5.    Pressing and Curing: Use a press to apply sufficient pressure and duration, ensuring full contact between the bonded surfaces. Finally, complete the curing process at room temperature or in an oven to achieve maximum strength.

IV.   Precautions

   To fully leverage the advantages of Benzene-free PU adhesive, the following precautions must be observed:

   1. Type Selection and Compatibility: Choose the appropriate model of Benzene-free PU adhesive based on different materials, processes, and performance requirements.

   2. Precise Control of Process Parameters: Drying temperature, time, and activation temperature are critical process points. Strict adherence to these parameters is necessary to avoid under-drying or over-drying.

   3. Environmental Management: Although benzene-based compounds are eliminated, good ventilation in the workplace must still be ensured to dissipate other volatile substances. Some benzene-free solvents remain flammable, so fire safety measures should not be overlooked.

   4. Storage Conditions: The adhesive should be stored sealed in a cool, dry place, avoiding high temperatures or freezing, and used within its shelf life.

Conclusion

    With the growing emphasis on green sustainability and increasing consumer health awareness, Benzene-free PU adhesive has become a green bonding solution that is gaining increasing attention in footwear manufacturing, thanks to its outstanding environmental features, strong comprehensive performance, and mature process adaptability. If you have any questions during product selection or usage, please feel free to contact us for professional product and solution support.