GP-421 Silicone Resin Emulsion

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Price is dependant on quantity, please request a quote for more information. If you are interested in samples, please refer to our sample price policy.


GP-421 is an emulsion of a reactive, further curable silicone resin in water carrier (GP-422). Heating substrates treated with GP-421 will accelerate cure of the resin component of GP-421, with the following schedule determined for aluminum substrates:

Substrate Temperature
Cure Time
150°C (302°F)
8 Hrs.
175°C (347°F)
3 Hrs.
200°C (392°F)
1 Hr.

Cure times at various temperatures will be reduced on substrates such as masonry, because of the alkaline nature of masonry, which helps catalyze the resin curing reaction.

Typical Properties
White, Opaque Liquid
Weight/Gallon @ 25°C
8.0 lbs
Flash Point (P.M.C.C.)
Specific Gravity
Solids Content
Solvent Content
Silicone Resin Content


GP-421 may be applied to porous substrates such as wood, leather, textiles or masonry to impart water repellency properties - blocking penetration of liquid water, while still allowing moisture in the vapor phase to pass through. GP-421 may be used as a component in paints or coatings intended primarily for exterior applications, where the silicone resin component will improve weathering resistance and allow moisture transfer. Some more specific applications are listed below:

  • Latex Paint Additive (Improved Weathering)
  • Binder in High Temperature Paints
  • Aqueous Adhesive Formulations

Processing and Safety Guidelines

GP-421 should be mixed prior to use to insure homogeneity. Refer to Safety Data Sheet for safety requirements.


GP-421 is supplied in 5-gallon (40 lbs.) pails, 55-gallon (440 lbs.) drums and 330-gallon (2640 lbs.) totes. Keep container tightly sealed. Do not freeze. Do not store above 100° F.