Acrylic Butter-Grade 221™
Formulated for flexibility and strength, Acrylic Butter-Grade 221 is a high-solids, water-based elastomeric sealant that uses advanced acrylic technology to reinforce and protect critical roof areas.
- Forms a durable, weather-resistant waterproof seal
- Ideal for sealing cracks, joints, penetrations, and small openings
- Highly flexible to accommodate surface movement
- 100% acrylic elastomeric formulation compatible with WeatherStar coating systems
- Superior adhesive and cohesive strength
- Plasticizer-free formulation resists drying and brittleness
- Contains built-in mildewcide and fungicide protection
- Easy-to-use, water-based formulation with simple clean up
- Non-toxic and VOC-compliant caulk system
- Solids by Volume
- 66% ± 2%
- Elongation
- 200%
- Tensile Strength
- 325 psi
- Viscosity
- 90,000 ± 10,000 cps
- Weight per Gallon
- 11.3 ± .2 lbs. per gallon
- Flash Point
- N/A
- Hardness (Shore A)
- 45
- Permeability
- 5 perms/inch. 20 mils thick coating
- Dry Time
- 2-24 hours
- Service Temperature
- -40° to 200°F
- Metal
- Modified bitumen
- TPO
- PVC
- EPDM
- Spray polyurethane foam
- Smooth built-up roofing
- Surface Preparation
Ensure the surface is clean, dry, and free of debris, grease, mildew, and loose material before application. If necessary, pressure wash (2,500–3,500 psi) to remove contaminants.
Inspect and repair damaged areas before applying the product. Depending on the substrate’s age and condition, a primer may be required.
- Mixing/Thinning
Mix thoroughly with a drill mixer for ~3 minutes to achieve uniform consistency. If thinning is necessary, dilute up to 10% (1:10 ratio). Consult Technical Services for specific guidance.
- Application Methods
Depending on project requirements, apply using a trowel, putty knife, stiff-bristled brush, or extrusion equipment.
- Coverage Rate
Coverage varies by substrate, application method, and required thickness. Refer to application guidelines for specific rates.
- Cure Time
Forms a surface skin within 2–4 hours under normal conditions. Full cure occurs in 7–10 days, depending on temperature and humidity.
- Limitations/Precautions
Do not apply below 50°F. In cold weather, store indoors until use to maintain consistency. Avoid application if rain is imminent, as water-based mastics can wash off before curing. Allow for proper drying under favorable conditions.
- Storage/Handling
Store in a cool, dry location away from sunlight and heat. Seal containers when not in use to prevent contamination.
Avoid freezing temperatures, as this can irreversibly damage the product, rendering it unusable.
- Cleanup/Disposal
Clean tools and equipment with soap and water immediately after use. Dried material may require mechanical removal.
Do not dispose of liquid material in drains or waterways. Follow local, state, and federal regulations for proper disposal of unused product and empty containers.
