Belzona 4361
Flexible Chemical Resistant Coating
A flexible, crack-bridging chemical resistant coating that maintains barrier integrity under substrate movement.
A flexible, high-performance, two-component barrier coating with outstanding chemical resistance and crack-bridging capability for substrates subject to movement.
- SeriesBelzona 4000 Series
- Documents4
Overview of Belzona 4361
Belzona 4361 is a flexible, high-performance, two-component barrier coating with outstanding resistance to a broad range of chemicals, particularly acids and alkalis. Where conventional rigid coatings would crack and fail under substrate movement, Belzona 4361 maintains its barrier integrity — elongation of 20% per ASTM D412 and crack-bridging of 0.38 mm gap width per German DIBt standards.
The brush- or squeegee-applied coating is supplied in black or red. Surface gloss is 90–100 gloss units (60° specular, ASTM D2457). The 3:1 by weight Base-to-Solidifier ratio mixes to a thixotropic liquid with sag resistance greater than 500 µm (20 mils). With a heat distortion temperature governed by Tg of 79°F (26°C) and DSC degradation onset of 266°F (130°C), the coating is suited to ambient and moderately heated chemical service.
Key Benefits
Outstanding resistance to a wide range of chemicals
100% solids formulation reduces health and safety risks in confined spaces with no shrinkage on cure
No solvents, no shrinkage during cure
Bonds strongly to virtually any rigid surface
Lightweight material that will not overload existing structures
Application Areas
What this product handles, grouped by equipment area — each links to the full application.
Tanks & Chemical Containment Areas
5 applications- Chemical containment liningProtection of tanks and secondary containment areas from chemicals and the effects of corrosionLearn more
- Acid-retaining walls, drains & channelsAcid retaining walls subject to thermal cycling or substrate movementLearn more
- Anti-slip walkways & access surfacesWalkways with non-slip aggregate incorporatedLearn more
- Bund wall/coating for chemical, acid, alkali containment zonesAcid spills in containment areas demand a lining rated for the specific concentration, temperature, and dwell time of the worst-case release rather than a generic chemic…Learn more
- Tanks, bunds, chemical zonesChemical containment areas fail when concrete porosity, joint shrinkage, and existing crack networks let spilled product travel into the substrate and through the bund w…Learn more
Technical Data
Composition
- Type
- Two-component, flexible, chemical-resistant barrier coating
- Mixing Ratio by Weight (Base : Solidifier)
- 3 : 1
- Mixing Ratio by Volume (Base : Solidifier)
- 2.8 : 1
Components
- Base
- Thixotropic liquid, black or red, gel strength 85–135 g/cm³, density 1.24–1.28 g/cm³
- Solidifier
- Clear liquid, yellow/brown, viscosity 3.6–4.2 poise at 77°F (25°C, BS 5350-B8), density 1.08–1.12 g/cm³
Mixed Properties
- Color
- Black or Red
- Density
- 1.19–1.23 g/cm³
- Viscosity (BS 5350-B8)
- 27.5–28.1 poise at 77°F (25°C)
- Sag Resistance (BS 5350-B9)
- Greater than 500 µm (20 mil)
- 60° Specular Gloss (ASTM D2457)
- 90–100 gloss units
- VOC (ASTM D2369 / EPA ref. 24)
- 3.44% (41.57 g/L)
Application & Coverage
- Application Methods
- Brush or squeegee
- Application Temperature Range
- 59°F (15°C) to 86°F (30°C)
- Recommended System
- Two-coat at 10 mil (250 µm) per coat (16 mil/400 µm total)
- Theoretical Coverage
- 33.4 ft² (3.1 m²) per 1.5 kg unit at 16 mil (400 µm)
- Volume Capacity
- 76 cu.in. (1,240 cm³) per 1.5 kg unit
- Working Life at 68°F (20°C)
- 30 minutes
Compressive Properties (ASTM D695, 68°F/20°C cure & test)
- Compressive Strength
- 20,615 psi (139.4 MPa)
- Proportional Limit
- 9.52 MPa
- Young's Modulus
- 0.08 × 10⁵ psi (53.3 MPa)
Flexural Properties (ASTM D790, 68°F/20°C cure)
- Flexural Yield Strength
- 940 psi (6.5 MPa)
Tensile Properties (ASTM D412, Die C)
- Tensile Strength (68°F/20°C cure)
- 3,490 psi (24.1 MPa)
- Tensile Strength (104°F/40°C cure)
- 4,480 psi (30.9 MPa)
- Elongation (68°F/20°C cure)
- 20%
- Elongation (104°F/40°C cure)
- 16%
Adhesion
- Pull-off, dry concrete (ASTM D4541/ISO 4624, 68°F cure)
- 810 psi (5.6 MPa)*
- Pull-off, damp concrete
- 780 psi (5.4 MPa)*
- * Cohesive failure of substrate (per ISO 13640 & EN 196 concrete)
Abrasion (Taber, ASTM D4060, 1 kg load, per 1,000 cycles)
- Dry (CS17 wheels)
- 62.9 mm³
Hardness
- Shore D (ASTM D2240, 68°F cure)
- 60
Impact Resistance (Izod Pendulum, ASTM D256, 68°F cure & test)
- Reversed Notched
- 34.7 KJ/m² (439.1 J/m)
- Un-Notched
- 42.5 KJ/m² (442.2 J/m)
- Falling Weight (ASTM D2794)
- Greater than 78.7 in.lbs (0.91 kg.m)
Heat Resistance
- Tg (ISO 11357-2, 68°F cure)
- 79°F (26°C)
- Dry Heat (DSC ISO 11357)
- 266°F (130°C) onset
- Service
- down to -40°F (-40°C)
Low Temperature Flexibility
- Maintains flexibility down to 32°F (0°C); passes ASTM D552 mandrel test at minimum 16 mm diameter (11.5% elongation)
Crack Propagation on Concrete
- Per German DIBt standards, at crack propagation rate of 0.02 mm/min, the system typically achieves a gap width of 0.38 mm before failure
Fire Resistance
- BS EN 13501-1 reaction to fire
- Class E
Chemical Resistance
- Excellent resistance to a broad range of chemicals, particularly acids and alkalis
- Refer to Chemical Resistance chart for detailed compatibility information
Shelf Life
- Separate Base and Solidifier components have a 2-year shelf life from date of manufacture in original unopened containers stored between 41°F (5°C) and 77°F (25°C). Refrigeration of this product will extend the shelf life.
Working Life
From commencement of mixing, use within:
- 59°F (15°C)
- 60 minutes
- 68°F (20°C)
- 30 minutes
- 86°F (30°C)
- 20 minutes
- 104°F (40°C)
- 15 minutes
Curing Time
Allow Belzona 4361 to solidify before subjecting it to the conditions indicated:
At 59°F (15°C)
- Light pedestrian traffic
- 7 hours
- Vehicular traffic
- 48 hours
- Full chemical resistance
- 14 days
At 68°F (20°C)
- Light pedestrian traffic
- 5 hours
- Vehicular traffic
- 36 hours
- Full chemical resistance
- 7 days
At 77°F (25°C)
- Light pedestrian traffic
- 4 hours
- Vehicular traffic
- 24 hours
- Full chemical resistance
- 6 days
At 86°F (30°C)
- Light pedestrian traffic
- 3 hours
- Vehicular traffic
- 20 hours
- Full chemical resistance
- 5 days
Service Temperature Limits
- Application Temperature Range
- 59°F (15°C) to 86°F (30°C) ideally
- Tg (ISO 11357-2, 68°F cure)
- 79°F (26°C)
- Dry Heat Resistance
- DSC degradation onset 266°F (130°C)
- Lower Service Temperature
- -40°F (-40°C); maintains flexibility down to 32°F (0°C)
- Storage Temperature
- 41°F (5°C) to 77°F (25°C); refrigeration extends shelf life
- Application
- Below 59°F (15°C) cure times extend significantly and chemical resistance may be reduced
Product PDFs
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Frequently Asked Questions
What is Belzona 4361 (Flexible Chemical Resistant Coating) used for?
Belzona 4361 is a flexible, chemical-resistant epoxy coating designed for substrates that experience movement, thermal cycling, or vibration where rigid coatings would crack. It provides chemical protection combined with elongation properties, ideal for bunds, expansion joint coverage, and dynamic process equipment.
What is the mixing ratio of Belzona 4361 (Flexible Chemical Resistant Coating)?
The mixing ratio of Belzona 4361 (Flexible Chemical Resistant Coating) is 3 : 1 (Base : Solidifier) by weight and 2.8 : 1 (Base : Solidifier) by volume. Please see the Product Specification Sheet (PSS) for more information.
How do you apply Belzona 4361 (Flexible Chemical Resistant Coating)?
To apply Belzona 4361, the surface must be clean, firm, and dry, free of rust, paint, and other surface contaminants, and conditioned with Belzona 4911 (Magma TX Conditioner). Add the entire Solidifier to the Base unit and mix thoroughly until homogeneous. Apply within 30 minutes to the prepared surface using a short-bristled brush, roller, or squeegee. Apply a second coat within the recommended overcoat window for full chemical resistance. Please see the Instructions for Use (IFU) for more information.
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