When we perform some bonding operations, we will choose different adhesives, as long as it can stick and stick firmly. Polyurethane adhesives and epoxy adhesives are also adhesives, but we must distinguish them before using them. So what is the difference between the two?
1. Polyurethane adhesive has slightly lower bonding strength and is easy to yellow, but its wear resistance and toughness are relatively high. One component can be moisture-cured at room temperature, and the required conditions are lower. Epoxy adhesives have high bonding strength and shear strength, and they have a wide range of applications. They can bond most materials except polyolefin materials, and are called universal adhesives. One-component epoxy adhesives require higher temperatures and may require heating or special treatment.
2. Both polyurethane adhesive raw materials and epoxy resin adhesive raw materials are actually toxic. For example, polyurethane curing agents are mostly isocyanates, which have high activity and are more harmful to human kidneys. The organotin in the catalyst is a poisonous or highly toxic chemical raw material. Amine curing agents in epoxy resin adhesives are also toxic, and reactive diluents are poisonous or highly toxic chemical raw materials. However, let us point out that these two adhesives are basically non-toxic after curing, so it is not clear which type is less toxic, but the application is slightly different.
3. There are differences between polyurethane adhesives and epoxy adhesives, but there are also many intersecting areas, such as the bonding of wood, stone, metal, and fiberglass in building materials. The former can be used for those with high toughness requirements, such as the bonding of shoe soles and uppers in the shoe industry. Epoxy adhesives can be used for high strength requirements.
Therefore, only after we correctly distinguish between polyurethane adhesive and epoxy adhesive, can we choose the right adhesive to bond all kinds of things. Adhesives are different, so in many ways, they are different.
