| Product Type | Moisture-curing polyurethane reactive hot-melt adhesive, commonly abbreviated as PUR hot melt | Combines initial hot-melt bonding with secondary moisture curing, producing stronger and more durable bonds than conventional thermoplastic hot melt in many applications. | Reactive chemistry and controlled manufacturing conditions generally make PUR more expensive than standard EVA or polyolefin hot-melt adhesive. |
| Typical Application Areas | Woodworking, edge banding, profile wrapping, automotive interiors, textiles, footwear, electronics, and composite assembly | Application requirements determine the required open time, viscosity, curing rate, flexibility, heat resistance, and moisture resistance. | Special grades for difficult substrates, rapid curing, low application temperature, or high flexibility may carry a premium. |
| Reactive Isocyanate Content | Common commercial PUR grades: approximately 2.0%–4.0% free NCO, depending on formulation | Higher reactive content can support faster or stronger moisture curing, but may increase sensitivity to moisture and require tighter handling controls. | Do not compare prices without checking the free-NCO specification because products with different reactivity levels are not directly equivalent. |
| Viscosity at Application Temperature | Approximately 2,000–20,000 mPa·s, commonly measured at 120–140°C | Lower viscosity can improve wetting and application speed; higher viscosity may provide better gap filling and bead stability. | Viscosity must match the equipment, nozzle size, coating method, and substrate. A mismatch can increase adhesive consumption and production waste. |
| Application Temperature | Typically 100–140°C; the exact setting depends on viscosity and equipment | Lower-temperature application can reduce energy consumption and help protect heat-sensitive substrates. | Low-temperature or high-speed grades may cost more but can reduce energy use, thermal damage, and line-start losses. |
| Open Time | Approximately 10–180 seconds, depending on grade, coating weight, temperature, and humidity | Longer open time supports large or complex assemblies; shorter open time can improve production speed. | Selecting the wrong open time may cause poor wetting, premature skin formation, or repositioning problems, increasing reject rates. |
| Initial Green Strength | Usually develops within seconds to several minutes after cooling, depending on formulation and assembly pressure | Higher initial strength allows faster handling and reduces the need for long clamping times. | Grades optimized for rapid handling may have a higher unit price but can lower labor and fixture costs. |
| Final Cure Time | Commonly 24–72 hours at approximately 20–25°C and moderate humidity; full cure depends on bond thickness and conditions | Moisture availability, temperature, humidity, bond-line thickness, and substrate permeability directly affect curing speed. | Very thick or moisture-impermeable bond lines may require controlled humidity, longer storage, or a formulation designed for slower diffusion. |
| Bond-Line Flexibility | Ranges from flexible to semi-rigid, depending on polymer structure and formulation | Flexible grades accommodate vibration, thermal expansion, and substrate movement more effectively. | Flexible or elastic grades may be priced above general-purpose grades because of specialized raw materials and formulation requirements. |
| Moisture and Heat Resistance | Often suitable for demanding indoor and selected outdoor applications after complete curing; performance must be verified by testing | Resistance varies with substrate, cure conditions, temperature exposure, and chemical contact. | High-resistance grades typically require additional formulation controls and may involve higher testing and certification costs. |
| Indicative Bulk Price | US$3.20–US$6.50 per kg | Bulk resin pricing is influenced by isocyanates, polyols, additives, energy, labor, quality controls, and market conditions. | Indicative range for larger commercial orders on an ex-works or FOB basis; it is not a confirmed quotation for a specific product code. |
| Small-Order Price | US$5.00–US$9.00 per kg | Small orders create higher proportional costs for production scheduling, packaging, testing, inventory, and documentation. | Request prices by quantity breaks such as 25 kg, 100 kg, 500 kg, and 1,000 kg to identify the most economical order size. |
| Packaging Options | Common formats include 2–5 kg moisture-barrier bags, 20–25 kg pails, and larger sealed industrial containers | Moisture-resistant packaging is essential because premature exposure to humidity can cause skinning, curing, or contamination. | Smaller packages improve handling but increase packaging cost per kilogram. Larger packages usually reduce unit cost but require suitable dispensing equipment. |
| Shipping and Storage | Store sealed in a cool, dry place, commonly around 5–25°C unless the technical data sheet specifies otherwise | Temperature fluctuations and moisture exposure can shorten usable storage life and affect viscosity or reactivity. | Freight, dangerous-goods classification where applicable, insurance, customs, and temperature-controlled handling can materially change landed cost. |
| Shelf Life | Commonly 6–12 months in the original unopened moisture-barrier packaging; verify the product-specific date | Older material may show increased viscosity, skin formation, or reduced application consistency. | Buying excessive volume may reduce the apparent unit price but increase the risk of expiration and disposal costs. |
| Landed Cost Formula | Product price + packaging + inland transport + freight + insurance + duties/taxes + testing and handling | The lowest factory price does not always produce the lowest delivered cost. | Compare suppliers using the same Incoterm, currency, order quantity, packaging format, destination, and payment conditions. |
| Quality Verification | Check technical data sheet, safety data sheet, batch number, viscosity, open time, NCO content, curing behavior, and bond strength | Consistent quality reduces downtime, rejected assemblies, rework, and unexpected adhesive consumption. | Request a production sample and conduct trials on the actual substrates and equipment before approving a large purchase. |
