Technical Bulletin
April, 2007
3
VHB
™
Tape Glass Bonding and
Silane Coupling Agents
Company
Contact
Products*
Premixed 3M
Available through distributors 3M™ Silane Glass Treatment
(ready to use)
that carry 3M™ VHB™ Tapes. AP 115
www.3m.com/vhb
(4 oz. pump spray or 1 gal. bottle)
Custom-Pak Products, Inc. ph) 262-251-6180
Gap-1: one time use pads
N118 W18981 Bunsen Drive fax) 262-251-6243
Gap-4: 4 oz. pump applicator
Germantown, WI 53022 dberg@custompakproducts.com Gap-11: 11 oz. aerosol
Gap 128: 1 gallon container
Concentrated Lancaster Synthesis, Inc. ph) 800-238-2324
4992: 25, 100, & 500 ml container
(mix by
P.O. Box 1000
fax) 603-889-3326
customer) Windham, NH 03087
www.lancastersynthesis.com
*Please consult the manufacturer for further information regarding specific products.
Which Silane Coupling
Agents Work With
3M™ VHB™ Tapes.
There are many silane coupling agents available commercially. Most of them are designed as
additives for materials such as fiberglass, since they create a bond between the glass fibers and
the matrix resin. For use with 3M™ VHB™ Tapes, we have found that the best performance is
obtained with 3-Glycidoxypropyl trimethoxysilane resin. The following source list is suggested
for the user’s evaluation in light of the user’s particular purpose and method of application.
How Long Will This
Solution Be Effective.
For premixed silane adhesion promoters, the shelf life is typically 12 months, as these
products are manufactured under rigorous conditions and process controls. Be sure to check
the expiration date on any premixed or concentrated silane solution before using. When
concentrated silane coupling agents are activated with water by the customer, it is best to use
this solution within two months. The effectiveness of either premixed or customer mixed
silane-cleaner solutions will be reduced if the shelf life is exceeded. It is important to consult
the manufacturer for specific shelf life recommendations for each product used.
How Are the Solutions
Prepared and Applied.
No special preparation is required for premixed silane coupling agents. For concentrated
silane solution, discussions with the suppliers’ technical personnel as well as 3M laboratory
evaluation suggests that a 0.5 wt. % level of silane coupling agent diluted in a 91:9 isopropyl
alcohol (IPA):water cleaning solution is optimum.
* After addition of the silane coupling agent
it is important that the solution is mixed thoroughly and allowed to hydrolyze (activate) for
8 hours before applying it to the glass surface. If hot water is used, the solution should be
usable in 30 minutes.To apply either the pre-mixed or customer mixed concentrated primer-
cleaner solution, spray on the surface of the glass or moisten a clean towel or cloth and treat
the glass in the bonding area. Wipe the glass vigorously until it is completely dry and no film,
streakiness or residue is visible. Since the silane coupling agent is incorporated into the
cleaning solution, no extra process steps are added. However, the glass surface should be
cleaned first with a 50:50 blend of IPA:water if the glass is excessively dirty prior to the silane
treatment of the glass. Under normal room temperature conditions it is best to wait 1 to 3
minutes before applying the tape so that any residual moisture can evaporate.
*Be sure to read and follow silane and solvent manufacturer’s precautions and directions for
use for proper handling and storage information.
Suggested Sources For
Silane Coupling Agents:
When to Use a Glass
Primer (Silane
Coupling Agent).
Silane coupling agents should be used any time 3M™ VHB™ Tape is being used to bond to
glass and is expected to perform in a high humidity environment or where frequent contact
with water is encountered. Examples of some applications utilizing these primers include
muntin bars bonded to glass windows, mounting letters to glass storefronts for outdoor signs
and viewing windows for equipment expected to perform in the presence of water.
