Update:Structural and pressure-sensitive adhesives
Adhesives may be broadly divided in two classes: structural and pressure-s...
Structural and pressure-sensitive adhesives
Adhesives may be broadly divided in two classes: structural and pressure-sensitive. To form a permanent bond, structural adhesives harden via processes such as evaporation of solvent (for example, white glue), reaction with UV radiation (as in dental adhesives), chemical reaction (such as two part epoxy), or cooling (as in hot melt). In contrast, pressure-sensitive adhesives (PSAs) form a bond simply by the application of light pressure to marry the adhesive with the adherend.
Pressure-sensitive adhesives are designed with a balance between flow and resistance to flow. The bond forms because the adhesive is soft enough to flow, or wet, the adherend. The bond has strength because the adhesive is hard enough to resist flow when stress is applied to the bond. Once the adhesive and the adherend are in proximity, there are also molecular interactions such as van der Waals forces involved in the bond, which contribute significantly to the ultimate bond strength. PSAs exhibit viscoelastic (viscous and elastic) properties, both of which are used for proper bonding.
In contrast with structural adhesives, whose strength is evaluated as lap shear strength, pressure-sensitive adhesives are characterized by their shear and peel resistance as well as their initial tack. These properties are dependent, among other things, on the formulation, coating thickness, rub-down and temperature.
"Permanent" pressure-sensitive adhesives are initially pressure-sensitive and removable (for example to recover mislabeled goods) but after hours or days change their properties, by becoming less or not viscous, or by increasing the bond strength, so that the bond becomes permanent.
Applications
Pressure-sensitive adhesives are designed for either permanent or removable applications. Examples of permanent applications include safety labels for power equipment, foil tape for HVAC duct work, automotive interior trim assembly, and sound/vibration damping films. Some high performance permanent PSAs exhibit high adhesion values and can support kilograms of weight per square centimeter of contact area, even at elevated temperature.[citation needed] These build adhesion to a permanent bond after several hours or days.
RUICO is a company specializing in pressure-sensitive adhesives, and has cooperation with mining companies in many countries. If you have any needs in this regard, please contact us.
Jimmy yuan
Zhejiang Ruico Advanced Materials Co., Ltd. (Stock No.873233)
Add: No.188, Liangshan Road, Linghu Town, Nanxun District, Huzhou City, Zhejiang Province, China 313018
Phone: +86 (572) 2903236
Fax: +86 (572) 2905222
WhatsApp: +86 15088303595
Website: www.ruicoglobal.com
Email:[email protected]