NanoFlame Surface Pretreatment
The NanoFlame surface pretreatment is used to alter the surface energy of a substrate in order to improve wetting and so give better adhesion to adhesives or coatings. This flame pretreatment device is based on the principle of flame-pyrolytic surface silicating. The NanoFlame burns a special propane-butane-organosilicon gas mixture, which is easily replenished.
The NanoFlame NF02 generates a very thin (20-50nm), but very dense, layer of silicon dioxide by flame-pyrolytic deposition of an organosilicon compound. These silicon dioxide layers produce very high surface energies and adhere strongly on:
- Polymeric materials
This layer provides the basis for long term water and solvent resistant adhesive bonds. The NanoFlame NF02 is recommended for the pre-treatment of small and medium sized surfaces up to A4 size.
The surface of the substrate is treated for a short period of time with the outer (oxidizing) part of the fame, which should continuously be moved during operation. It is very important that the treatment is never done with inner blue (reducing) part of flame. If necessary, the illumination of the working site can be reduced for better differentiation.
In case of pre-treating very small, thin walled or heat sensitive parts, it is recommended to repeat the flaming in short intervals. As a rule of thumb, an area of 1 cm² requires a treatment time of 3-5 seconds. Local overheating should be avoided. Generally, the temperature of the pretreated parts should not exceed 150-200°C. Particular care has to be taken in case of thermoplastic materials.
The storage time of the flame pretreated part should not exceed 12 hours. Storage at slightly elevated temperatures – up to 50°C – is favourable.
Empty flame device can be refilled with NanoFlame gas mixture from 200 resp. 600ml cartridges.
Safety and Transport Regulations
NanoFlame is a special propane-butane-organosilicon gas mixture and forms like pure propane-butane propellants explosive mixtures with air. Hence, open sources of ignition have to be removed, smoking during work with NanoFlame is not allowed.
Additional Recommendations for Surface Pretreatment of PTFE
Particular care has to be taken, when PTFE or other fluoropolymers are pretreated. PTFE and other fluoropolymers decompose at temperatures above 350°C. Some of these decomposition products are very toxic after inhalation. Therefore, it is absolutely necessary, that the flame pretreatment is carried out considering the instructions given under 2. In particular, the flame has to be moved to avoid overheating. Small or thin-wall parts require interrupted treatment. For obtaining the intended effect no higher temperatures than 100°C are necessary when treating such polymers.
Preparation of the substrate surfaces prior to adhesive bonding is mandatory step of the bonding or coating process! All substrate surfaces must be thoroughly cleaned and degreased. It is strongly recommended to run a simple wettability test prior to applying any adhesive, coating or paint on your substrates! Using Polytec PT test inks (with defined surface energy) is a very decent and quick method to evaluate the surface tension (surface energy) of your substrates. It is a very easy-to-use tool for surface determination for quality assurance and production to determine whether the surface has to be pre-treated or not.
For this purpose Polytec PT offers 8 different test inks which cover the range from 25 mN/m - 66 mN/m.