PRODUCT DESCRIPTION
LOCTITE 3541 is a reactive hot-melt adhesive based on polyurethane prepolymers. The adhesive is pressure sensitive and gives a high initial strength instantly after joining the parts. Additionally it has a long open time to be suitable for automatic or manual assembly line.
The adhesive provides the following characteristics:
| Colour: | Transparent when molten, after cooling light ivory |
| Odour: | Weak |
| Density: | 1.15±0.05g/cm3 |
| Solids: | 100% |
| Voiscosity: | 6000-10000mPa.s @110degC |
| Equipment: | Brookfield Thermosel, Spindle 27 |
| Open time: | 2-4 min |
| ApplicationTemperature: | 110 to 140 degC |
| Temperature resistance: Short-term (up to 1 h) | -30 to 100 degC-30 to 120 degC |
Pretreatment
The bonding surfaces must be clean, dry and free of oil and grease. Substrate temperature should not fall below 20degC during application. Lower temperatures will lead to and early solidification of the adhesive and thus to a reduced open time, possibly the adhesive might even flake off. If necessary the substrates may be preheated, however longer open times and thus extended cycle times will have to be taken into consideration at temperatures above 45degC.
Application
LOCTITE 3541 can be applied from heatable cartridge guns, from usual syringe type melting equipment. At longer rest periods melting and application temperatures should be decreased. Longer exposure to higher temperatures can lead to a viscosity increase.
Curing
LOCTITE 3541 cures exclusively by moisture and gains its final strength after 1-5 days, but exhibits high handling strength instantly after joining.
Curing is a chemical reaction depending on the following
parameters:
- Humidity in the rooms of application and storage
- Humidity of the substrates
- Permeability of the substrates to be bonded
- Application weight/ layer of the adhesive film
