In sealants and adhesives, fumed silica plays a major role in rheological control and viscosity strength.

When fumed silica is added and dispersed in adhesives and sealants, a silica agglomerates network is formed, agglomerates react with SI-OH and result in hydrogen bonds, thus flowing property is restricted and viscosity increased, thickening property promoted.

But, when shear thinning is applied, hydrogen bonds and silica network breaks, viscosity decreases, this allows adhesives and sealants to be applied smoothly; when shear thinning is removed, network is restored, viscosity increasing, this prevents adhesives and sealants from sagging during the curing process.

What functions fumed silica brings to Adhesives & Sealants?

  • To be applied smoothly when being sprayed or under high mechanical stress;
  • Keep high viscosity during storage or transport or when it adheres to the substrate;
  • Tailored viscosity available according to requirements of different applications;
  • Enhances the strength of cured adhesives;
  • Prevent sedimentation or sagging, improve dispersion performance;
  • Viscosity is less affected by heat or high temperature.

HIFULL® Fumed Silica Product Has Below Excellent Properties

  • Tailored Rheology Control
  • Great anti-sag & anti-settling properties
  • Ideal Transparency
  • Durable water-resistance & fire-resistance

Organic Silicone Adhesives 

As reinforcing filler, fumed silica has excellent reinforcing properties and it’s used to improve the mechanical properties of silicone sealant, and can improve its rheological properties.

Epoxy Adhesive

Fumed silica is a very efficient rheology control agent with functions of sag resistance, mechanical property adjustment, and keeping viscosity stability during storage. When added in appropriate amounts, epoxy adhesives can exhibit excellent rheological properties.

MS/SMP/SPU Adhesives

The polar groups have affinity for the silyl hydroxyl groups on the surface of fumed silica, and the fumed silica gathers around the polar groups in large quantities, and produces synergistic effects and bridging effects with hydroxyl or amino compounds to promote thickening and thixotropic effects.

Acrylic Adhesives

After the shear force is removed, the fumed silica network and hydrogen bond reorganization are restored, preventing the precipitation of adhesives and sealants during storage and sag during curing.

Solvent or Liquid Adhesives

Fumed silica has large specific surface area, strong adsorption performance and easy suspension. It can absorb a large number of water molecules in water and swell into extremely fine particles to form a stable suspension. It is an ideal anti-settling agent.

Hot-melt Adhesive (HMA)/ Hot Glue

Under the action of electrostatic repulsion and steric repulsion, the primary particles of fumed silica or smaller agglomerates shield the van der Waals attraction, so that the particles no longer aggregate and maintain higher stability.

Application In Adhesives(HIFULL® Product Advisor)

SystemFunctionRecommend DosageHydrophobic Fumed Silica SuggestHydrophilic Fumed Silica Suggest
Epoxy Adhesivesag-resistance, settling-resistance1.5%-3.0%0.25%-2.0%HB-139
HB-151
HL-200
HL-300
Polyurethane Adhesivesag-resistance, rheology control, thixotropic, viscosity increase1%-5%HB-139
HB-151
HL-200
HL-300
Acrylic, cyan acrylic, Anaerobic acrylic, UV-cured acrylic adhesivessettling-resistance, rheology control, thixotropic 1%-5%HB-139
HB-151
HL-200
HL-300
Organic silicone adhesivesreinforce, rheology control5%-15%HB-132
HB-630
HB-620
HB-612
HB-615
HL-150
HL-200
MS/SMP/SPU adhesivessag-resistance, rheology control, thixotropic, viscidity increase 1%-5%HB-151
HB-139
HL-200
Rubber-based adhesives (BR /CR /NR)rheology control, thixotropic, reinforce1%-5%4%-8%HB-151HL-200
Pressure sensitive adhesivesviscidity increaserheology control, thixotropic1%-5%4%-8%/HL-200

Application In Sealants(HIFULL® Product Advisor)

SystemFunctionRecommend DosageHydrophobic Fumed Silica SuggestHydrophilic Fumed Silica Suggest
Polyurethane Sealantssag-resistance, thixotropic, extrusion efficiency, stability( moisture control)3%-7%HB-139
HB-151
HL-200
Acrylic Sealantssag-resistance, settling-resistance, rheology control, thixotropic, extrusion efficiency3%-7%HB-151HL-200
Organic siliconesag-resistance, reinforcement, rheology control, thixotropic, extrusion efficiency, stability( moisture control)5%-15%HB-132
HB-630
HB-620
HB-612
HB-615
HL-150
HL-200
MS/SMP/SPU sealantsreinforce,extrusion efficiency,stability( moisture control)5%-10%HB-139
HB-151
/
butyl rubber-based sealantssag-resistance, reinforce3%-7%HB-151HL-200
Polysulfide sealantReinforce, rheology control, thixotropic,3%-7%HB-151
HB-139
HL-200

ABOUT HIFULL


Our main products are fumed silica SiO2, fumed titanium dioxide TiO2, and fumed alumina Al2O3. We get 20+ years of expertise and 12,000 tons of annual capacity. We supply total of 23 grades of hydrophilic & hydrophobic fumed silica. We get registration of REACH and pre-registration of K-REACH & KKDIK. We are the leading setting body of ISO18473-1:2015ISO18473-3:2018, and ISO 23157:2021. Learn More About Hifull

Hello, Customers

My name is Van, I’m the business manager of HIFULL, I have been in Fumed Silica Industry for more than 10 years. Feel free to contact me. I’m happy to provide you the best service and products.
Van
Business Manager