Polyurethane adhesives are widely used in multiple fields due to their excellent bonding performance, flexibility and fatigue resistance. To ensure its optimal performance and guarantee operational safety, the following key points should be noted during use:
1. Surface treatment is the core
The surface treatment of the materials to be bonded is the most crucial link that determines the success or failure of the bonding. First of all, it is necessary to thoroughly remove contaminants such as grease, dust, moisture, rust and mold release agents from the surface to be bonded. Organic solvents (such as acetone, ethyl acetate) can be used for cleaning, but the adhesive should be applied only after the solvents have completely evaporated. Secondly, for inert materials (such as PP, PE, and metals), the surface needs to undergo activation treatment, such as grinding, sandblasting, or using a dedicated primer, to increase surface roughness and activity, significantly enhancing bonding strength and durability. The treated surface should be protected from recontamination.
2. Environmental conditions need to be controlled
Environmental temperature and humidity have a significant impact on the curing process of polyurethane adhesives, especially moisture-curing single-component products. The ideal construction environment temperature is usually between 15 and 30 degrees Celsius, and the relative humidity is preferably between 50% and 70%. Excessively low temperatures can lead to a slow reaction rate, incomplete curing, and a brittle adhesive layer. If the temperature is too high, it may shorten the applicable period and make it impossible to operate in time. Low humidity makes it difficult for one-component adhesives to cure, while high humidity may cause them to cure too quickly, generating a large number of bubbles and affecting the density and strength of the adhesive layer. In addition, the environment should be kept well-ventilated.
3. The mixing ratio must be precise (for two-component products)
For two-component polyurethane adhesives, it is essential to accurately weigh Component A (the main agent) and Component B (the curing agent) strictly in accordance with the proportion specified in the product manual. Proportional deviation will directly lead to incomplete molecular structure of the cured product, seriously affecting the final bonding strength, chemical resistance and weather resistance. It is recommended to use an electronic scale for weighing and adopt mechanical stirring to ensure uniform mixing. The mixed adhesive solution should be used up within the specified "applicable period". Once the adhesive solution thickens or gels, it cannot be used anymore.
4.Operation and Safety Protection
Operators should take good personal safety precautions. Wear protective gloves, goggles and masks to avoid direct contact of the adhesive with skin and eyes. If it accidentally gets on the skin, it should be washed immediately with soapy water. If it comes into contact with the eyes, rinse with plenty of water and seek medical attention. Open flames should be strictly prohibited on site as many polyurethane adhesives and their thinners are flammable. Uncured adhesives and waste solvents used for cleaning must be classified and treated in accordance with regulations and must not be dumped at will.
5. The curing process should be thorough
After gluing and bonding, sufficient pressure must be applied to ensure that the adhesive layer is in full contact with the adherend and to expel air bubbles. The curing process requires sufficient time and should not be rushed. It should be ensured that the initial curing is completed under the specified conditions (pressure, temperature, time), and during the subsequent curing period (usually several hours to several days), excessive stress should be avoided to achieve the final strength.
In conclusion, strictly adhering to the technical requirements of the product manual, doing a good job in surface treatment, environmental control, precise proportioning and personal protection are the keys to the successful use of polyurethane adhesives and achieving reliable bonding effects.
