Polyurethane adhesive mainly consists of ammonium isocyanate, polyol, polyether containing hydrocarbon, polyester and epoxy resin, filler, catalyst and solvent. It has many excellent properties, such as high reactivity, room temperature curing, impact resistance and so on.
Polyurethane adhesive is generally divided into two basic types: one is moisture curing type, and the other is reactive curing type. The single component adhesive is easy to construct, but the curing is slow; the two components have the advantages of fast curing and good performance, but they need to be compounded in use, and the process is complex. Each has its own future. According to whether there is fluidity, polyurethane adhesive can be divided into non sagging type and self flowing parallel type. The non sagging type is used for vertical, inclined, ceiling and other occasions. Before curing, it will not offset, slide or flow due to the self weight of the adhesive strip; while the self flowing flat door is used for horizontal occasions. According to the properties after use, it can also be divided into non drying type, semi drying type and curing elastic type. The following small series on polyurethane adhesive and epoxy adhesive differences to you do the following detailed introduction, come to understand it!
The adhesive strength of polyurethane adhesive is small and easy to turn yellow, but its wear resistance and toughness are high. One component polyurethane adhesive can be cured at room temperature, and the required conditions are low. The adhesive strength and shear strength of epoxy adhesive are relatively high, and it can be applied to a wide range of materials, except for polyolefin materials. It is called energy adhesive. Single component epoxy adhesives require higher temperatures and may require heating or special treatment.
Polyurethane adhesives and epoxy resin adhesives are toxic in fact. For example, polyurethane curing agents are mostly isocyanates with high activity and great harm to human kidney. Organotin in catalyst belongs to toxic or highly toxic chemical raw materials. The amine curing agent in the epoxy resin adhesive is also toxic, and the active diluent belongs to toxic or highly toxic chemical raw materials. However, we point out that the two adhesives are basically non-toxic after curing, so it is not clear which kind of toxicity is less, only the application is slightly different.
There are differences between polyurethane adhesive and epoxy adhesive, but there are also many cross domains, such as wood, stone, metal and FRP in building materials. The former can be selected for those with high toughness requirements, for example, the footwear industry can be used for the bonding of sole and upper. For high strength requirements, epoxy adhesive can be selected.
