Choosing the right industrial adhesive depends on the substrates being bonded, required bond strength, flexibility, working time, application method and service environment. Polyurethane (PU), epoxy, polyvinyl acetate (PVA) and contact adhesives use different bonding technologies, making each suitable for particular manufacturing, woodworking, construction and repair applications.
In summary: Polyurethane adhesives are widely used for timber assembly, flooring and composite lamination. Epoxy adhesives are commonly selected for rigid bonding, gap filling and repairs. PVA adhesives are well suited to close-fitting woodworking joints, while contact adhesives provide rapid initial grab for laminates, upholstery and flexible materials.
| Property | Polyurethane | Epoxy | PVA | Contact |
|---|---|---|---|---|
| Curing mechanism | Moisture reaction or two-component cure | Resin and hardener reaction | Water loss and film formation | Solvent or water evaporation |
| Bond flexibility | Rigid to flexible, depending on grade | Generally rigid | Generally limited | Often flexible |
| Water resistance | Formulation dependent | Generally good when fully cured | Dependent on D classification | Formulation dependent |
| Gap filling | Selected grades | Selected grades | Limited | Generally unsuitable |
| Typical substrates | Timber, flooring, foam, panels | Timber, metals, composites | Timber, wood-based panels | Laminates, rubber, upholstery |
| Key processing factor | Moisture, temperature and open time | Mix ratio, pot life and cure | Joint fit, pressure and drying | Flash-off time and pressure |
These are general adhesive characteristics. Actual performance depends on the formulation, substrate preparation, joint design and service conditions. Always consult the relevant product technical data sheet (TDS).
Polyurethane adhesives are available as moisture-curing single-component systems and two-component reactive systems. Moisture-curing formulations react with available moisture to form a polyurethane or polyurethane-urea network. Cure speed depends on temperature, humidity, adhesive thickness and substrate moisture.
PU adhesives are used in timber manufacturing, flooring installation, engineered wood production, insulated panels and composite lamination. Different formulations provide different working times, viscosity, flexibility and bond performance.
Fortis polyurethane products include:
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Epoxy adhesives are generally supplied as two-component resin and hardener systems. Once mixed at the specified ratio, they chemically cure to form a crosslinked polymer network.
Epoxy adhesives are commonly used where rigid bonding, dimensional stability or gap filling is required. Applications include timber repair, fibreglass, compatible metals and composite assemblies.
Correct mixing ratio, surface preparation, application temperature and curing conditions are essential. Epoxy performance can vary considerably between formulations, particularly in flexibility, heat resistance and moisture tolerance.
Fortis AD822 is a two-component epoxy adhesive for compatible timber bonding and repair applications.
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Polyvinyl acetate adhesives are water-based dispersions commonly used for timber assembly, cabinetmaking, furniture and wood-based panels. Bond formation occurs primarily through water loss and polymer film formation.
PVA adhesives are generally straightforward to apply and clean up before drying. They perform particularly well in properly prepared, close-fitting timber joints with suitable clamping pressure.
Water resistance varies by formulation. D3 and D4 classifications describe resistance to specified moisture exposure conditions under EN 204; they do not automatically establish structural load-bearing suitability.
Fortis AD317 is a D3-rated PVA adhesive for compatible woodworking and timber applications.
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Contact adhesives are commonly based on elastomeric polymers supplied in solvent-based or water-based formulations. They are generally applied to both mating surfaces and allowed to reach the specified bonding condition before joining.
Unlike many reactive adhesives, contact adhesives provide rapid initial grab when the coated surfaces are brought together under firm pressure. They are particularly useful for laminates, upholstery, rubber, fabrics and compatible flexible substrates.
Correct adhesive coverage, flash-off time and contact pressure are essential. Contact adhesives are generally unsuitable for filling gaps or replacing structural epoxy and polyurethane systems.
Fortis contact and rubber adhesive options include AD215, AeroBond AD40 and PA75 for selected applications.
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| Application | Recommended Fortis Product | Selection Consideration |
|---|---|---|
| Fast timber assembly | AD5105 PU | Shorter working time |
| General timber bonding | AD5205 PU | Assembly and processing time |
| Longer timber assembly | AD5405 PU | Extended working time |
| Structural timber | Fortis structural PU range | Required certification and process |
| Composite panel lamination | AD5113 PU | Substrate compatibility and curing |
| Rigid timber bonding and repair | AD822 Epoxy | Mixing, joint design and cure |
| Furniture and woodworking | AD317 PVA | Joint fit and moisture exposure |
| Contact bonding | AD215 or AeroBond AD40 | Application method and flash-off |
| Flexible PVC and rubber | PA75 PU contact adhesive | Material compatibility |
Product recommendations are application starting points, not substitutes for compatibility testing or technical approval. Structural timber applications require an adhesive with certification appropriate to the intended joint and service conditions.
Surfaces should be clean, sound and free from contaminants such as oils, grease, dust and incompatible coatings. Some substrates require abrasion, cleaning or specialised pretreatment to achieve reliable adhesion.
Working time determines how long components can be assembled after adhesive application. Cure time determines when sufficient strength develops for handling or service. These are different properties and must not be confused.
Moisture influences the curing of single-component polyurethane adhesives and the drying of water-based PVA systems. Temperature affects viscosity, working time and cure rate. Excessive moisture can cause foaming in some polyurethane formulations.
Bond-line thickness, contact area, substrate fit and applied pressure affect adhesive performance. Contact adhesives require firm contact pressure, while timber and structural adhesives may require controlled clamping or pressing.
Consider water exposure, heat, chemicals, movement, mechanical loading and long-term durability. No adhesive chemistry should be assumed suitable for every service environment.
For substrate-specific guidance, read How to Choose an Adhesive for Different Materials.
Not necessarily. Both can produce strong timber bonds. Performance depends on formulation, joint design, substrate preparation and test conditions. Polyurethane may offer advantages in selected mixed-material or moisture-exposed applications, while PVA is well suited to close-fitting timber joints.
Epoxy is often selected for rigid bonding, repair and gap filling. Polyurethane is commonly used for timber manufacturing, flooring and composite lamination. The better choice depends on the substrates, flexibility requirements and service conditions.
Generally not for rigid structural bonding. Contact adhesives are primarily intended for surface bonding requiring rapid initial grab and, in many applications, flexibility.
PVA is suitable for many woodworking joints, polyurethane is widely used in timber assembly and selected structural applications, and epoxy is useful for specialised timber bonding and repair. Choose according to the joint design and exposure conditions.
Not all polyurethane adhesives are waterproof. Water resistance varies by formulation, test classification and service conditions. Continuous immersion requires specific product approval.
Open time is the period available after adhesive application before assembly must be completed. Curing time is the period required for the adhesive to develop its specified properties. Both depend on the formulation and application conditions.
No. D4 describes water resistance under EN 204. Structural suitability requires separate evidence and applicable certification for the intended load-bearing application.
Fortis Adhesives & Coatings manufactures industrial bonding products for timber, construction, composite lamination and manufacturing. Our technical team can assist with adhesive selection, substrate compatibility, working time and production requirements.
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