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This product is a reactive polymer waterproof coating consisting of Components A and B, where Component A is a polyurethane prepolymer and Component B is a curing agent. To use, mix Components A and B are mixed in a specific ratio, stirred until uniform, and then applied to the substrate. After several hours, the mixture reacts and cures to form a continuous, flexible, and seamless rubber waterproofing layer.
Products are classified into Type I, Type II, and Type III based on their basic performance characteristics.
Products are classified as exposed (E) or non-exposed (N) based on whether they are used in exposed conditions.
Products are classified into Category A and Category B based on the limits for hazardous substances.
Polyurethane Waterproof Coating—PU; Two-component—M; Exposed—E; Non-exposed—N.
Label in the following order: product name, components, basic performance characteristics, exposure status, limits for hazardous substances, and standard number.
Example: A Class I, exposed two-component polyurethane waterproof coating is labeled as:
PU Waterproof Coating M I E A GB/T 19250-2013
When applying the coating by scraping or brushing, it should be applied in multiple coats.
Substrate Preparation; Installation of Additional Waterproofing Layers in Detail Areas; Application of Waterproofing Membrane Over Large Areas; Quality Inspection and Acceptance; Installation of Protective and Separation Layers
Substrate Preparation: Remove dust and debris from the substrate surface; the substrate must be level, dense, and dry; defects such as hollow spots, loose areas, and sanding must be repaired; roof drains, vents, equipment, and sanitary fixtures must be securely installed with tight, level joints.
Mixing: Two-component polyurethane coatings are reaction-curing types and must be mixed in strict accordance with the specified ratio. Accurate measurement is required; after mixing Components A and B, the deviation must not exceed 5%. After accurately weighing the components, pour them into a mixing bucket and stir thoroughly with an electric mixer for 3 to 5 minutes. Each batch must be used within 20 to 30 minutes.
Application of Additional Layers: For vulnerable areas prone to leaks—such as inside and outside corners and pipes penetrating walls—additional layers are applied for reinforcement. At these reinforced areas, the “one fabric, two coats” or “two fabrics, three coats” method may be used, with polyester non-woven fabric preferred as the reinforcing substrate. When applying the coating, first apply one to two coats of the coating, then immediately lay the reinforcing fabric, and finally apply another coat of coating to cover the surface.
Large-Area Application: Large-area application may only begin after the additional layer at the joints has fully cured. For horizontal surfaces, pour the mixed coating evenly onto the substrate and then apply it with a trowel. For vertical surfaces, apply the coating with a trowel from the bottom up. A waterproof coating 1.5–2.0 mm thick should ideally be applied in 2–3 coats. The width of construction joints should not be less than 100 mm. Each coat should be applied in a direction perpendicular to the previous one.
It is widely used in concealed waterproofing and seepage prevention projects for railways, tunnels, bridges, tracks, culverts, reservoirs, roofs, underground structures, restrooms, and other similar applications, and can also be used for waterproofing in non-exposed roofing projects.
Applicable Standard: GB/T 19250-2013 “Polyurethane Waterproof Coatings”
| No. | Item | I | II | III | |
| 1 | Solid content, % ≥ | 92.0 | |||
| 2 | Surface drying time, h ≤ | 12 | |||
| 3 | Actual work time, h ≤ | 24 | |||
| 4 | Flowability | 20 minutes, no visible tooth marks | |||
| 5 | Tensile strength, MPa ≥ | 2.00 | 6.00 | 12.00 | |
| 6 | Elongation at break, % ≥ | 500 | 450 | 250 | |
| 7 | Tear strength, N/mm ≥ | 15 | 30 | 40 | |
| 8 | Low-Temperature Flexibility | -35°C, no cracks | |||
| 9 | Impermeability | 0.3 MPa, 120 min—water-tight | |||
| 10 | Heat Expansion Coefficient, % | -4.0 to +1.0 | |||
| 11 | Bond strength, MPa ≥ | 1.0 | |||
| 12 | Water absorption rate, % ≤ | 5.0 | |||
| 13 | Aging at a Fixed Elongation | Heat Aging | No cracks or deformation | ||
| Artificial Climate Aging | No cracks or deformation | ||||
| 14 | Heat Treatment
(80°C, 168 h) |
Tensile Strength Retention, % | 80 to 150 | ||
| Elongation at break, % ≥ | 450 | 400 | 200 | ||
| Low-Temperature Flexibility | -30°C, no cracks | ||||
Limits on Harmful Substances
| No. | Item | Category A | Category B |
| 1 | Volatile Organic Compounds (VOC), g/L ≤ | 50 | 200 |
| 2 | Benzene, mg/kg ≤ | 200 | |
| 3 | Toluene + Ethylbenzene + Xylene, g/kg ≤ | 1.0 | 5.0 |
| 4 | Phenol, mg/kg ≤ | 100 | 100 |
| 5 | Anthracene, mg/kg ≤ | 10 | 10 |
| 6 | Naphthalene, mg/kg ≤ | 200 | 200 |
| 7 | Free TDI, g/kg ≤ | 3 | 7 |
| 8 | Soluble Heavy Metals (Lead), mg/kg ≤ | 90 | |
| 9 | Soluble heavy metals (cadmium), mg/kg ≤ | 75 | |
| 10 | Soluble heavy metals (chromium), mg/kg ≤ | 60 | |
| 11 | Soluble heavy metals (mercury), mg/kg ≤ | 60 | |
