Excellent Substrate Adhesion
Dynasylan® Organofunctional silanes act as adhesion promoters or coupling agents between inorganic materials (glass, minerals, and metals) and organic polymers (thermosets, thermoplastics, and elastomers).
Silanes when used as adhesion promoters or as polymer modifier (e.g. PU prepolymer endcapper) can increase the adhesion of any Adhesive or Sealant with the substrate to be bonded.
As an illustration, Dynasylan® GLYMO improves the wet adhesion of an adhesive used to bond glass and aluminum:
Figure 1: Wet adhesion of a Latex Sealant on Aluminum and Glass, with and without Dynasylan® silanes.
Dynasylan® AMMO and Dynasylan® 1146 improve the dry adhesion on wooden surfaces:
Figure 2: Dry adhesion of a SMP-based adhesive with and without Dynasylan® silanes
In addition, the resulting bonded assembly will exhibit increased durability especially better resistance to the moisture that can appear between the Adhesive/Sealant and the substrate.
Various Dynasylan® products can act as Adhesion promoters:
| Adhesion Promoter |
Technical features |
| Dynasylan® 1146 |
Non-sensitizing, low VOC, prevent premature failure in wet environments, low yellowing |
| Dynasylan® 1124 |
Polymer modifier (endcapper), effective in PU systems, good adhesive properties on hard-to-bond materials |
| Dynasylan® SIVO 210 |
Can be used as a cost-effective aminosilane system instead of AMEO, especially for oxime silicones |
| Dynasylan® AMMO |
Fast reacting aminosilane with well-balanced reactivities and good adhesion performance |
| Dynasylan® TRIAMO |
Triamino-functional silane with overall good adhesion performance in silicones |
| Dynasylan® SIVO 202 |
New aminosilane system for SMP and silicone based adhesives to improve adhesion to PVC |
| Dynasylan® SIVO 203 |
New aminosilane system for SMP and silicone based sealants to improve adhesion to plastics |
| Dynasylan® GLYMO |
Versatile silane for epoxies, latices, polysulfides and polyurethanes; excellent adhesion on glass |
| Dynasylan® GLYEO |
Environmentally friendly, no methanol release equivalent of Dynasylan® GLYMO, higher level of water stability |
Mechanical Strength and Properties
Whether the selected
Dynasylan® is an adhesion promoter, a crosslinker or a drying agent, adding silanes in your Adhesive or Sealant formulation will drastically
improve the uniformity of cure thereby
optimizing the mechanical performance.
In the case of Polyurethane prepolymers, silanes can be used as endcappers to react with the free NCO groups of the isocyanate-terminated PU. Endcapping provides key benefits to these hybrid systems:
- Higher mechanical performance
- Lower viscosity silane-modified prepolymer, faciliting any further processing
- Compliance with REACH regulation in Europe due to the reduction of free NCO groups in the Adhesive/Sealant
The silane adhesion promoter has a b impact on mechanical properties of SMP-systems:
Figure 1: Elongation of a SMP sealant CaCO3 filled SPU-sealant incl. 1,1 wt.-% silane adhesion promoter
There are several Dynasylan® grades that can help achieving/tailoring mechanical strength:
| Mechanical Strength Silanes |
Technical features |
| Dynasylan® DAMO-T |
Standard aminosilane, sensitizing, fast curing |
| Dynasylan® 1146 |
Preferred aminosilane for low modulus products, low VOC, low odour, non-sensitizing |
| Dynasylan® 1189 |
Best choice for products with high elasticity |
| Dynasylan® 1124 |
Recommended for high strength products
|
| Dynasylan® SIVO 202 |
New aminosilane system for SMP and silicone based adhesives to improve adhesion to PVC |
Dynasylan® 1189 is more than an endcapper, it greatly improves elongation:
Figure 2: Test in SPUR® - 1,1% Dynasylan® used
Storage Stability and Water Scavenger
Silanes used as drying agents can capture any latent moisture present in the immediate environment.
This moisture absorption capability helps to increase the shelf life of the stored product and to prevent any premature cure by avoiding the reaction between moisture and the active groups in the Adhesive or Sealant.
Figure 1: Shelf Life of a silane terminated polyurethane Sealant at 50°C,
with and without Dynasylan® Silanes. In this specific example, the recommended dosage is 1.4%.
On top of that, the
mechanical strength will be improved especially in the case of SMP (hybrid) Sealants.
Here are some Dynasylan® grades particularly suitable to improve
storage stability:
| Storage Stabilizing Silanes |
Technical features |
| Dynasylan® VTMO |
Product of choice, ideal reactivity to scavenge moisture |
| Dynasylan® VTMOEO |
High boiling point, suitable for e.g. polysulfide sealants |
| Dynasylan® 6490 |
Low VOC, low odor silane oligomer, acts as a chemical lid for freshly bottled adhesives |
Polymer Modification (endcapper)
Silanes can modify polymers either when used as a co-monomer during the polymer synthesis or when reacting with an already existing pre-polymer.
In addition to providing more formulation options and allowing NCO-free and bubble-free systems, Silane modification improves the overall performance of the polymer by helping to achieve:
- Improved mechanical performance (tensile strength, elongation at break, hardness)
- Good adhesion
- Scratch resistance
- Scrub resistance
- Thermal stability
- Weathering stability
- Good electrical properties
Several Dynasylan® grades can be used as Polymer modifiers:
| Polymer modifying Dynasylan |
Technical features |
| Dynasylan® 1189 |
Ideal PU Endcapper, less polar, improves UV stability |
| Dynasylan® 1122 |
Fast reaction with NCO groups (also without catalyst), increased cohesion through double silicon function, methanol free |
| Dynasylan® 1124 |
Fast reaction with NCO groups (also without catalyst), increased cohesion through double silicon function |
| Dynasylan® MEMO |
Methacrylate-functional silane, suitable for e.g. acrylics |
| Dynasylan® VTMO |
Vinyl-functional silane, suitable for grafting or copolymerization within polyolefins |
| Dynasylan® VTEO |
Vinyl-functional silane, methanol free, suitable for water-based products |
Crosslinking
Dynasylan® products have long been used to crosslink polymers such as silicones, polyethers, epoxies, polyethylenes, polyacrylates, polyurethanes, and others. Crosslinking occurs in the presence of moisture.
This cost-efficient technology is used in many application fields.
As an example, Dynasylan® Organofunctional silanes are used to crosslink tailormade RTV-1 alcoxy silicones to seal shower stalls, structural glazing for all-glass constructions, etc.
| Crosslinking Dynasylan® |
Technical features |
| Dynasylan® A |
Tetrafunctional, methanol free |
| Dynasylan® 40 |
Multifunctional, ethoxysilane oligomer, VOC reduced |
| Dynasylan® P |
Tetrafunctional, slower reactivity |
| Dynasylan® VTMO |
Trifunctional, less crosslinking sites |
| Dynasylan® PTMO |
Trifunctional, lower reactivity |
Chemical resistance
Silanes added in the formulation as adhesion promoters, endcappers and/or crosslinkers
increase the crosslinking density of the Adhesive or Sealant and improve the
performance of the assembly against chemicals even in harsh conditions.
Dynasylan® AMMO and Dynasylan® 1189, when used in SPU Sealants, improve the shear resistance even when joints are immersed 22 days in Isopropanol.
Figure 1: Lap shear strength of an SPU Sealant after 22 days ageing in Isopropanol
(Test performed on Aluminum)
The following Dynasylan® grades are recommended when Adhesives and Sealants formulators are looking for improving the chemical resistance:
| Chemical Resistance Silanes |
Technical features |
| Dynasylan® AMMO |
Adhesion promoter; non-sensitizing, fast curing |
| Dynasylan® 1189 |
Endcapper, fast-reacting with free NCO groups, no side reaction, UV stable, higher hydrophobicity compared to AMMO
|
Moisture Resistance
As adhesion promoters and PU endcappers, Silanes increase the durability of adhesion between the Adhesive or Sealant and the substrate. They provide
better resistance to moisture and
prevent premature adhesion failure.
Dynasylan® 1189 and low VOC Dynasylan® 1146 oligomer are the right Silane solutions to
prevent adhesion failure when Adhesives or Sealants are in a humid environment.They help to
improve the shear resistance of an SPU sealant even when a joint is immersed 6 days in water.
Figure 1: Lap shear strength of an SPU Sealant after 6 days ageing in water at room temperature
(Test performed on Aluminum at 23°C)
In addition, Dynasylan® 1146 can minimize water uptake in MS Polymer sealants:
Figure 2: Water uptake - Dynasylan® 1146 in MS Polymer Sealants For this test,
the hybrid sealant specimen was stored in H2O at 23°C
Dynasylan® 1189 and Dynasylan® 1146 can help Adhesive and Sealant formulators to increase the moisture resistance of the final product:
| Moisture Resistance Silanes |
Technical features |
| Dynasylan® 1146 |
Non-sensitizing adhesion promoter, low VOC, imparts hydrophobicity |
| Dynasylan® 1189 |
Ideal PU Endcapper, less polar, improves UV stability |