Views:388 Author:Site Editor Publish Time: 2021-06-24 Origin:Site
PUR (Polyurethane Reactive) is called moisture curing reactive polyurethane hot melt adhesive in Chinese. The main component is isocyanate-terminated polyurethane prepolymer. The adhesion and toughness (elasticity) of PUR can be adjusted, and it has excellent bonding strength, temperature resistance, chemical resistance and aging resistance. Has become one of the important varieties in the adhesive industry. Now it is widely used in the national economic fields such as packaging, wood processing, automobile, textile, electromechanical, aerospace, etc. PUR adhesives are porous materials containing polar and chemically active urethane groups (-NHCOO-) or isocyanate groups (-NCO) in the molecular structure, and materials containing active hydrogen, such as wood, leather, fabric, paper, ceramics and other porous materials It has excellent adhesion to plastic, metal, glass, rubber and other smooth surface materials.
1. From the glue supply method: there are two types, air pump type and gear pump type.
2. Divided from the way of melting: there are two types, the melting cylinder type and the pressure plate type.
a. Melting tank type: The heating part is a thick-walled cylinder, usually made of aluminum alloy. The small package of rubber (rubber pellets) is put into it and heated to melt. There is a cover on the cylinder. This type of machine is often used in small laminators, but it is rare.
b. Pressure plate type: The heating part is an aluminum alloy heating plate. When using, the heating plate is pressed into the plastic barrel from top to bottom. The heating plate is located above the plastic. When the heating plate is heated, only the upper layer of glue and heating When the disc is in contact, it will melt when it reaches the melting point. The lower part of the rubber barrel is not heated at this time. How much is needed during production, and how much is melted, so as to prevent the glue from aging and deterioration due to long-term heating. The glue is isolated from the air when melting the glue: There is an O-ring seal between the heating plate and the inner wall of the glue barrel, so that the melted liquid glue will not come into contact with the air, which ensures the PUR use condition requirements. The pressure plate is made of aluminum alloy precision casting and CNC precision processing. The outer surface of the heating plate is treated by DuPont Teflon deep penetration sintering, which has the advantages of high coating strength and not easy to fall off. The glue on it is easy to remove, can effectively prevent the glue from carbonization, ensure the best glue quality, and reduce the blockage of the glue delivery system.