SILANE OLIGOMERS - PROVIDING SOLUTIONS AND OPTIMIZATION


Silane oligomers are functional silanes grafted together via Si-O-Si linkage. They allow formulators of coatings, adhesives and sealants to improve performance of the coated substrate(s). They have several unique benefits over traditional silanes.

What are Silane Oligomers?

Silane oligomers are short chain polymers of silane monomers, bonded together at the siloxy linkage. The number of monomers in this comb-like structure is typically 10 to 100.

These oligomers bond to the substrate with greater efficiency once hydrolyzed. Due to their orientation, less silane is caught up within the coating or adhesive and more at the interface as a functional layer. These functional layers strengthen bonds between inorganics and organics resulting in improved rub and mar resistance, improved water resistance and decreased VOC concern.

Example: The structure of CoatOSil MP-200, an oligomer of the Silquest A-187 monomer [bracketed as the repeating unit]

Oligomeric Silanes Structure

 

What are the benefits of silane oligomers over traditional silanes?

Flexibility of use - water and solvent based products
Oligomeric silanes, due to their structure, can be formulated into either water or solvent based products providing long term shelf stability and improved adhesion to organic substrates, filler and pigments. Most silanes can be used in solvent based products or in waterbased primers (when the primer is formulated and used in a short period of time - pH dependent, up to a few days). This flexibility can allow formulators to achieve improved adhesion and shelf stability in water based coatings without limiting shelf stability.

VOC/HAP reduction
In creating the Si-O-Si bonds between each silane group, over 60% of the methanol or ethanol is driven out of the silane, yielding large reductions of HAPs or VOC (depending on whether the initial monomer is a methoxy or ethoxysilane).

Improved Durability/Rub Resistance
Pre-reacting the silanes into oligomers changes them into hydrophobic additives. When used as a replacement for a latex cross linker or as a high solids paint crosslinker, oligomeric silanes can improve wet scrub resistance dramatically.

Improved hydrophobicity
Due to the Si-O-Si bonds in the silane oligomers are more hydrophobic than standard silanes. This benefit translates directly to the formulated product. Imagine the potential applications of a water based, hydrophilic coating with great adhesion to metal, concrete or masonry.

Improved adhesion vs traditional silanes
Oligomeric silanes migrate toward towards inorganic substances and result in a stronger bond than standard silanes, which can become bound in the coating or adhesive itself. This layer is also more uniformly oriented, forming a stronger tie later to organic resins.

 

What oligomeric silanes are out there?

Momentive manufactures several oligomeric silanes including
CoatOSil MP200, Silquest VX 225, and Silquest Y-15744.

 

CoatOSil MP-200

  • Epoxy silane oligomer based on the Silquest A-187 monomer
  • Can be used in either water, solvent based
  • 100% active material - water and solvent free
  • Lower alcohol content in final product
    • Lower VOC contribution than A-187 or similar epoxy silanes
  • Greater functionality
    • Should result in lover loading rates overall to achieve same or better results
  • Better stability
    • Improved hydrolysis resistance
    • Can be used in water based formulations to achieve shelf stability >6 months
  • Low viscosity
  • Used in slightly acidic acrylic latex emulsions to graft onto latex, functionalizing with silane to improve adhesion and crosslinking in finished formula
  • Can be used to treat metallic particulates minimizing H2 off gassing
 

Silquest VX-225 at a glance

  • Amino functional silane based on the Silquest A-1110 monomer
  • Slower more controlled cure than standard amino functional silanes
  • Lower yellowing than standard amino functional silanes
  • Lower residual tack
    • Lower dirt pick up during drying/post dry
  • Increased hydrophobicity of the resultant coating
  • Improved adhesion to porous substrates - concrete, masonry and others
  • Lower formulation viscosity
  • Improved elongation
    • Acts as internal plasticizer in elastomeric formulations
    • Can enable joint movement in RTV Silicone formulations
  • Lower toxicity due to polymeric nature
  • Low VOC/no HAPs
 

Silquest Y-15744 at a glance

  • Designed for use in silicone or hybrid adhesives and sealants
  • Based on a monomer similar to Silquest A-1110
  • Maintains fast cure of amine functional silanes
  • Lower residual tack
  • Improved wetting
  • Increased hydrophobicity
  • Improved elongation
    • Acts as internal plasticizer in elastomeric formulations
    • Can enable joint movement in RTV Silicone formulations
 

Where can I learn more?

Please reach out to ChemPoint, Momentive's sole national distributor for additional information on these value driven oligomeric silanes. Please feel free to contact us by phone or email to further discuss:
 
Karl Sjoberg: 425.378.8565 | Karl.Sjoberg@ChemPoint.com
Nick Murray: 425.372.9037 | Nick.Murray@ChemPoint.com
 
We look forward to working with you on your unique formulation needs