Polyurethane Adhesives
Polyurethane adhesive is a compound, able to tenaciously join different materials and is used in many sectors owing to its tenacity and endurance features, which, once it permanently hardens, acquires a very strong resistance both to water and to solvents.
Despite the traditional adhesives, the polyurethane one offers the following advantages:
- highly versatile chemistry;
- flexible and rigid;
- bonds a big variety of products;
- slow to fast curing time;
- good low temperature properties;
- good environmental and water resistance;
- good chemical and oil resistance.
The effectiveness of polyurethane adhesive is based on a surface adhesion (adhesion) and the power of attraction of the adhesive molecules exerted between themselves (cohesion).
The adhesion between the surfaces of two materials in contact with each other, is then measured as the force required to separate them.
To ensure the effectiveness, it is important that the temperature of the working environment is not lower than + 10 ° C and above + 35 ° C and that the surfaces are thoroughly dry, clean and free from dust, grease, release agents and other contaminants. Each adhesive has a minimum application temperature, under which the polymerization will not guarantee anymore a product with such strong adhesive features. Its evident characteristics and the easy application, allow the use of the polyurethane adhesives in many areas, as aviation, boating and building.
APPLICATION SECTORS AND TYPES
The obvious features of tenacity and endurance and its ease of use allow the use of polyurethane adhesive in many sectors.
For a cold application, it is possible to find single component and double component adhesives, both diluted in solvents and, most of them, with 100% of solid content (without VOC – volatile organic compounds). Some application fields:
Insulation
sandwich panels, multilayer panels, insulated panels, cold rooms, walls for thermal insulation or protection against sound, noise barriers, etc.
Transportation
insulated and isothermic vans, refrigerated bodies, caravans, etc.
Air conditioning
air treatment, pipes, etc.
Furniture and furnishings;
Aviation and boating industry
Floors;
Gluing of parquet or linoleum floors;
Construction and building:
roofs, profiles, frames, doors and windows, prefabrication of metalwork and construction site support, etc.
ventilated facades
Panels for ventilated facades
Wood
structures, for furniture, etc.
PVC
coating, plating, etc.
Agglomerated
cork, rubber, plastics, etc.
Heating and bathroom fittings:
toilet facilities, reinforcements and shower systems, bathroom furniture, bathtubs and shower bases, ceramic tiles, etc.
Lighting and energy
solar panels, lighting, etc.
Safety
fire doors, etc
Other
HOW TO CHOOSE THEE MOST SUITABLE ADHESIVE
La colla poliuretanica è un composto capace di unire tenacemente diversi materiali e viene utilizzata in molteplici settori proprio per le sue caratteristiche di tenacia e di resistenza che una volta indurita in maniera definitiva acquisisce una resistenza molto forte sia all’acqua che ai solventi.
Analysis of the surfaces requiring gluing
At least one of the two surfaces is porous
Both surfaces are compact
Consistency of the adhesive
Fluid-liquid, easy to apply, surfaces with low absorbance, application by spraying or by pouring, greater elasticity.
consistent, hard to apply, application by casting, stiffness and structured.
Time available/required from the distribution of the adhesive to bonding
The gluing surface is wide, long time between distribution and bonding
Surface requiring gluing not too wide, fast bonding process.
SURFACE PREPARATION
To obtain a durable, tenacious and resistant bonding, before spreading the glue on the adhering surfaces, it is recommended to suitably prepare them in order to be sure to achieve a strong grip.
For example, in the case of particularly smooth surfaces, which offer less adhesion compared to coarse surfaces, sanding or sand blasting treatments are recommended and, then, proceed with surface degreasing.
If solvent is used in this last operation, it is necessary to wait for the surfaces to dry completely before spreading polyurethane adhesives.
To obtain a better adhesion, it is also recommended to use primers, which make the surface more responsive for a correct adhesion. It is necessary to leave the primer to dry completely before applying the adhesive.
EXAMPLES OF APPLICATION
ONE COMPONENT ADHESIVE WITHOUT FILLERS
Sandwich panel wood-compact foam-wood
Adhesive name: 1k 04 V12
Viscosity (at 25°C): about 2.000 mPa·s
Open time (at 25°C with Ur 50%): 12 min
Pressing time (25°C): 1h 20′
Complete hardening: 3-4 days
Rubber agglomerates
Adhesive name: 1k 03 V60
Viscosity (at 25°C): about 5.000 mPa·s
Open time (at 25°C with Ur 50%): 1 h
Pressing time (25°C): 4 h
Complete hardening: 4-5 days
Ventilated tile facade – expanded polystyrene –rolled section
Adhesive name: 1K 03 V10
Viscosity (at 25°C): about 5.000 mPa·s
Open time (at 25°C with Ur 50%): 10′
Pressing time (25°C): 1h 10′ – 1h 30′
Complete hardening: 3-4 days
ONE COMPONENT ADHESIVE WITH FILLERS
Air ducts
Adhesive name: 1K 02C V40
Viscosity (at 25°C): about 15.000 mPa·s
Open time (at 25°C with Ur 50%): 40′
Pressing time (25°C): 20h
Complete hardening: about 4-5 days
Sandwich panels for irregular expanded: rock wool (soundproofing panel)
Adhesive name: 1K 01C V15
Viscosity (at 25°C): ca 10.000 mPa·s
Open time (at 25°C with Ur 50%): 15 min
Pressing time (25°C): 1h 45′
Complete hardening: about 4 days
PVC bonding for coating
Adhesive name: 1K 03C V60
Viscosity (a 25°C): about 12.500 mPa·s
Open time (a 25°C e con Ur 50%): 1 h
Pressing time (25°C): 4h 15′
Complete hardening: about 8 days
TWO COMPONENT ADHESIVE WITHOUT FILLERS
Insulating panels for nautical sector
Adhesive name: 2k 02 V6
Viscosity A+B (at 25°C): about 7.000 mPa·s
Open time (at 25°C with Ur 50%): 6 min
Pressing time (25°C): 2h
Complete hardening: 4 days
Photovoltaic module assembly
Adhesive name: 2k 02 V3
Viscosity A+B (at 25°C): about 7.000 mPa·s
Open time (at 25°C with Ur 50%): 3 min
Pressing time (25°C): 2h
Building panels – drywall: 3 days
Building panels – drywall
Adhesive name: 2k 07 V11
Viscosity A+B (at 25°C): tixotropica
Open time (at 25°C with Ur 50%): 11 min
Pressing time (25°C): 1h – 1h 30′
Complete hardening: 4-5 days
TWO COMPONENT ADHESIVE WITH FILLERS
Vans – refrigerated trucks
Adhesive name: 2K 09C V100
Viscosity A+B (at 25°C): about 15.000 mPa·s
Open time (at 25°C with Ur 50%): 1 h 40′
Pressing time (25°C): 5h – 6h
Complete hardening: 5-6 days
Fire doors
Adhesive name: 2K 05C V70
Viscosity A+B (at 25°C): about 10.000 mPa·s
Open time (at 25°C with Ur 50%): 1 h 10′
Pressing time (25°C): 9 h
Complete hardening: 6 days
PVC / Aluminum frames with mineral wool filling
Adhesive name: 2K 11C V120
Viscosity A+B (at 25°C): ca 2.000 mPa·s
Open time (at 25°C with Ur 50%): 2 h
Pressing time (25°C): 8 h
Complete hardening: 6 days