![]() ![]() These require the use of an adhesion promoter for stable bond strength. EPDM, neoprene) can have low surface energy and may also contain plasticizers and oils. There are several 3M™ VHB™ Tapes that are formulated to be resistant to plasticizer migration, or 3M™ Scotch-Weld™ Plastic Adhesive 2262, thinned, can serve as a barrier to migration. Be sure to test the tape bond to the sealer on a metal surface to verify good adhesion.įlexible PVC (vinyl) contains plasticizers that can migrate into the tape and affect adhesion. To prevent a weakening of the bond, a lacquer or varnish should be applied to these surfaces. Silane coupling agents, added to the IPA/water cleaning solution, can help reduce the “water-loving” tendency of these surfaces and enhance the tape bond in high moisture environments.Ĭopper, brass, and bronze are prone to oxidation even after the 3M™ VHB™ Tape is applied. In basic terms, water vapor can undercut the tape bond and interfere with the normal adhesion forces. Normally, the hydrophilic nature makes pressure sensitive adhesive bond durability susceptible to change under high humidity or exposure to moisture. Glass, stone, ceramic or other siliceous materials are hydrophilic (water-loving) by nature. Exceptions to these abrading guidelines are 3M™ VHB™ Tapes 49, as they typically perform best on smooth glossy surfaces and abrasion may reduce the bond strength. Always clean the surface with the IPA/water solution or additional methods previously described, and be certain that all loose particles are removed prior to bonding. Avoid grinding a surface with coarse abrasive materials, since they may create too rough of a texture for the adhesive to adequately flow into the surface. Tools such as a power palm sander will assist on large jobs. Scotch-Brite® Hand Pads (such as 7447 Maroon or Heavy Duty Green) are good for achieving the right level of abrasion. A surface with many micro-scratches in it can have up to 40% additional available surface area, translating to higher ultimate strength and greater initial adhesion. Very small scratches in the surface, generated with circular motion rather than straight-line motion, are most desirable. When abrading, it is important for tapes to have a finely abraded surface. ![]() Smooth a surface to obtain more flatness, allowing improved contact area.Ībrasion often helps adhesion to paints and plastics.Create additional surface area that can increase adhesion.Remove heavy levels of dirt or oxide from metals or paints (e.g.When using solvents, be sure to follow the manufacturer’s precautions and directions for use when handling such materials.Ībrading a surface can serve several functions: Please consult your local Air Quality Regulations to be sure the cleaner is compliant. *Note: These cleaner solutions contain greater than 250 g/l of volatile organic compounds (VOC). In some cases, bond strength can be increased and ultimate bond strength can be achieved more quickly by exposure of the bond to elevated temperatures (e.g. At room temperature, approximately 50% of the ultimate strength will be achieved after 20 minutes, 90% after 24 hours and 100% after 72 hours. After application, the bond strength will increase as the adhesive flows onto the surface.(Steps C and D) Generally, this means that the tape should experience at least 15 psi (100 kPa) in roll down or platen pressure. Firm application pressure develops better adhesive contact and helps improve bond strength. Bond strength is dependent upon the amount of adhesive-to- surface contact developed.Typical surface cleaning solvents are IPA/ water mixture (rubbing alcohol) or heptane.* (Steps A and B) To obtain optimum adhesion, the bonding surfaces must be well unified, clean and dry.Unique Materials: Special surface preparation may be needed for glass and glass-like materials, copper and copper containing metals and plastics or rubber that contain components that migrate (e.g.need to be sealed to provide a unified surface. Porous Surfaces: Most porous and fibered materials such as wood, particleboard, concrete etc.Adhesion Promoters: Priming a surface can significantly improve initial and ultimate adhesion to many materials such as plastics and paints.Abrasion: Abrading a surface, followed by cleaning with IPA/water, can remove heavy dirt or oxidation and can increase surface area to improve adhesion.Heavy Oils: A degreaser or solvent-based cleaner may be required to remove heavy oil or grease from a surface and should be followed by cleaning with IPA/water.There are exceptions!Įxceptions to this general procedure that may require additional surface preparation include: Most substrates are best prepared by cleaning with a 50:50 mixture of isopropyl alcohol (IPA) and water* prior to applying 3M™ VHB™ Tapes. ![]()
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