
Technical Bulletin
Surface Preparation for 3M™ VHB™ Tape Applications
Heavy Oils On surfaces with a light oily film, or other light contamination, the IPA/water solution is usually
adequate. Where heavy oils or grease are present, a “degreasing” solvent such as 3M™ Prep Solvent 70,
3M™ Adhesive
Remover,
3M™
Citrus
Base
cleaner,
acetone,
mineral
spirits,
naphtha
or
similar
solvents
can be used
to cut the oil. When cleaning with solvents, always follow with an IPA/water clean to
remove any residue or film that may be present.
Abrasion
Adhesion
Promoters
Abrading a surface can serve several functions:
•
Remove heavy levels of dirt or oxide from metals or paints.
•
Create additional surface area that can increase adhesion.
•
Smooth a textured surface to obtain more flatness, allowing improved contact area and adhesion.
A finely abraded surface (approximately 180 to 320 grit scratch) can help adhesion to many paints and
plastics. Very small scratches on the surface, generated with circular motion rather than straight-line
motion, are most desirable. Micro-scratches on a surface increases the available surface area to bond to
resulting
in
greater
initial
adhesion
and
achieving
higher ultimate strength.
3M™
Scotch-Brite
® Hand
Pads (7447 Maroon or Heavy Duty Green) are optimal for achieving the right level of abrasion.
Powered sanders (e.g., palm or dual-action sanders) will assist on large surface areas. Avoid grinding a
surface with coarse abrasive materials, as they can create too much texture for the adhesive to adequately
flow into the surface. Always clean the surface with the IPA/water solution or methods previously
described, and be certain that loose particles are removed from the abraded surface prior to bonding.
Exceptions to these abrading guidelines are 3M™ VHB™ Tapes 4932 and 4952, as they typically
perform best on smooth, glossy surfaces and abrasion may reduce the bond strength.
Priming a surface can significantly improve initial and ultimate adhesion to many materials such as
plastics and paints because of their low surface energy or process additives they may contain. A primer
creates a new surface for 3M VHB Tape to adhere to and can also create a layer that may impede the
migration of additives that may be present in a material. It is important for the user to determine the
suitability of the 3M VHB Tape, the adhesion promoter and the application process.
Porous
Surfaces
Rough, porous or fibered materials such as wood, particleboard, cement, etc., have an open surface and
require sealing to provide a unified surface for tape bonding. Common sealing materials would include
paint, varnish or other hard surface coatings. Fast drying 3M™ Rubber and Vinyl Spray 80 can also be
used to unify the surface and improve the tape bond.
Unique
Surfaces
Glass, stone, ceramic or other siliceous materials are hydrophilic (water-loving) by nature. Normally,
the hydrophilic nature makes pressure sensitive adhesive bond durability susceptible to change under
high humidity or exposure to moisture. In basic terms, water vapor can undercut the tape bond and
interfere with the normal adhesion forces. 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.
Copper, brass, and bronze are prone to oxidation even after the 3M VHB Tape is applied. To prevent a
weakening of the bond, a lacquer or varnish should be applied to these surfaces. Be sure to test the tape
bond to the sealer on a metal surface to verify good adhesion.
Flexible PVC (vinyl) contains plasticizers that can migrate into the tape and affect adhesion. There are
several 3M VHB Tapes that are formulated to be resistant to plasticizer migration, or 3M™ Scotch-
Grip™ Plastic Adhesive 2262, thinned, can serve as a barrier to migration. Rubber materials (e.g.
EPDM, neoprene) can have low surface energy and may also contain plasticizers and oils. These
require the use of an adhesion promoter for stable bond strength. Test for compatibility with flexible
PVC and rubber materials by aging bonded samples for 7-days at 150°F (66°C) and check for
softening of the adhesive, discoloration or reduction in bond strength.
* Note: These cleaner solutions contain greater than 250 g/l of volatile organic compounds (VOC). Please consult your local Air
Quality Regulations to be sure the cleaner is compliant. When using solvents, be sure to follow the manufacturer’s precautions
and directions for use when handling such materials.
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