Acronal® NX 3587

Asphalt bleed-through is a persistent problem when coating bituminous roofing materials with white or light-colored reflective coatings. The mechanism involves volatile aromatic compounds and lighter oil fractions in asphalt migrating through the coating film, particularly when heated by sunlight. This causes yellow-brown discoloration, destroying the coating's reflectivity and aesthetic appearance within months. Conventional acrylic dispersions, especially styrene-acrylics, are particularly susceptible because aromatic styrene has affinity for aromatic bitumen compounds. Acronal® NX 3587 virtually eliminates this problem through its pure acrylic chemistry eliminating styrene's aromatic affinity, crosslinking functionalities creating a tighter molecular network that blocks migration, specific molecular weight distribution optimized to resist oil penetration, and enhanced film density from ambient crosslinking. BASF testing at 50°C with UV exposure shows NX 3587 exhibiting virtually no bleed-through compared to significant discoloration with standard acrylics. This makes it the premium choice for white reflective roof coatings over asphalt, bitumen, and modified bitumen substrates.

Acronal® NX 3587 contains reactive keto-carbonyl functionalities that undergo room-temperature crosslinking through ketone-hydrazine or similar chemical reactions. The process begins immediately after film formation and continues over days to weeks at ambient temperatures, progressively building the crosslinked network. Performance enhancements include dramatically increased tensile strength from ~400 psi initially to ~600 psi after full crosslinking, improved elongation maintenance at ~500% providing excellent crack-bridging, enhanced substrate adhesion particularly to polyurethane foam and bituminous surfaces, reduced water absorption from initially ~8% decreasing to ~5% after crosslinking, improved heat resistance maintaining integrity up to 50°C, better UV and weathering stability extending service life, and enhanced chemical resistance to roof contaminants. The crosslinking is automatic without catalysts or special curing, occurs effectively across typical roof temperature ranges (15-40°C), and progressively improves performance making newly applied coatings already good and fully cured coatings excellent. This ambient crosslinking is a key differentiator making NX 3587 superior to non-crosslinking pure acrylics for demanding roof applications.

Acronal® NX 3587 demonstrates excellent adhesion across roofing substrates. For Asphalt and Bituminous Surfaces including BUR (built-up roofing), APP/SBS modified bitumen, asphalt shingles, and rolled roofing felt, direct application is often possible after cleaning though a compatible primer can enhance adhesion on aged, weathered, or chalking surfaces. For Polyurethane and Polyisocyanurate Foam especially spray polyurethane foam (SPF) roofing systems, the enhanced adhesion of NX 3587 provides excellent bonding, typically without primers on fresh foam though aged foam may benefit from priming. For Metal Roofing (galvanized steel, aluminum, coated metals), appropriate metal primers are recommended before applying NX 3587-based coatings. For Single-Ply Membranes (TPO, EPDM, PVC) if over-coating is desired, surface preparation and compatibility testing are essential as some membranes may require specialized primers. For Concrete and Masonry roof surfaces, standard acrylic-compatible primers improve adhesion. Primer recommendations include asphalt/bitumen primer for aged or weathered bituminous surfaces, polyurethane primer for better adhesion on foam, metal primers for proper corrosion protection and adhesion on metal, and epoxy or acrylic primers for concrete. Always conduct adhesion pull-off testing on representative areas to verify bond strength exceeds 200 psi (1.4 MPa) before proceeding with full application. VUBS Corporation can recommend specific primers and surface preparation protocols.

White reflective roof coating formulations using Acronal® NX 3587 typically contain NX 3587 polymer at 25-35% of total formulation weight as the primary binder, Titanium Dioxide (TiO2) rutile grade at 15-25% for maximum solar reflectance (aim for 85%+ reflectance), Calcium Carbonate or other white fillers at 15-30% for rheology and cost optimization, Mica or platelet fillers (optional) at 2-5% to enhance reflectance and barrier properties, Defoamer at 0.2-0.4% to eliminate surface defects that reduce reflectance, Rheology modifiers (HEUR thickeners) at 0.5-1.5% for proper application viscosity and sag resistance, Dispersants at 0.3-0.6% for pigment stability, Preservatives at 0.1-0.3% for storage protection, and Water to balance. Application is typically by brush, roller, or airless spray at 1.5-2.5mm wet film thickness (0.8-1.5mm dry), usually in two coats for best coverage and reflectance. Target performance includes solar reflectance > 85% (ASTM C1549 or E903), thermal emittance > 0.85 (ASTM C1371), Solar Reflectance Index (SRI) > 100, tensile strength > 600 psi (ASTM D2370), elongation > 400% (ASTM D2370), water absorption < 5% (7-day immersion), and heat resistance maintaining properties at 50°C+. Formulations can achieve ENERGY STAR cool roof certification, CRRC (Cool Roof Rating Council) listing, LEED credits, and Title 24 California compliance. VUBS Corporation can provide complete starting formulations and technical optimization support.

Acronal® NX 3587 pure acrylic significantly outperforms styrene-acrylics in roof applications. Asphalt Bleed Resistance shows NX 3587 with virtually zero bleed vs severe yellowing in styrene-acrylics due to aromatic styrene attraction to bitumen. UV Resistance demonstrates pure acrylic with superior long-term stability vs styrene which oxidizes and degrades under UV. Color Retention shows NX 3587 maintaining white appearance for 10+ years vs styrene-acrylics showing yellowing in 2-5 years. Heat Aging shows crosslinked pure acrylic maintaining properties at 50-60°C vs styrene-acrylics showing softening and tack. Dirt Pickup Resistance is better with pure acrylic maintaining reflectivity vs styrene-acrylics accumulating surface contamination. However, trade-offs exist: Cost where NX 3587 is premium-priced vs economical styrene-acrylics, Scrub Resistance where styrene-acrylics can show advantages in some tests, and Processing where styrene-acrylics may offer easier formulation in some cases. For cool roof applications where long-term reflectance, bleed resistance, and durability justify premium pricing, NX 3587 is clearly superior. For lower-tier applications or non-bituminous substrates where bleed is not a concern, styrene-acrylics may suffice. The performance gap is most dramatic on asphalt substrates in hot, sunny climates where NX 3587's benefits fully manifest. VUBS Corporation can help evaluate cost-benefit for specific applications.