Parafilm

Parafilm is a stretchable, whitish translucent sealing film from - about 50:50 - paraffin wax and polyolefin ( polythene ), manufactured by Pechiney Plastic Packaging (formerly American National Can Company). In the chemistry lab, they will (even with an irregular edge, spout ) used to seal various vessels to avoid spilling, Litter and evaporation largely. In biological laboratories will parafilm, or the competing product Nescofilm, for sealing Petri dishes used. This procedure usually takes in cell and tissue culture applications and prevents drying of the explants and the medium as well as contamination by bacteria or fungi.

It is one of the simplest and most commonly used tools in the everyday laboratory work and comes from 1980 in roll form with release paper on the market. The extensibility allows the use of similar commercial cling film for the kitchen. The advantages of Parafilm are:

  • Thick (0.127 mm), and significantly more stretchable (up to 200 %). Elongation at break: 300%
  • Resistant to a variety of chemicals
  • Not resistant to benzene, chloroform, diethyl ether, carbon tetrachloride, toluene
  • Low gas and water vapor permeable
  • Only sticks to itself, if it has been stretched
  • Non-poisonous

Application areas and conditions

Parafilm can be used from -45 to 50 ° C, resistant to acids, alkalis, some alcohols, and for three years shelf life. However, he leaves behind small traces on the vessel, melts at 60 ° C (flash point 301 ° C) and is dissolved by highly volatile, non-polar organic solvents, such as benzene or ether or possibly already lifted under their vapor pressure.

By gentle heating of the overlapping edges, and finger pressure it can be fused together. With practice, vessels can be sealed so air-and liquid-tight.

Compared with the watch glass Parafilm is advantageous light, space-saving and shatter-proof. There are also lightweight unbreakable Clock " glasses " from the PTFE that can withstand higher temperatures. Even lower-cost aluminum foil is used for sealing and isolating, which is, however, attacked by acids and alkalis, is not liable, does not seal, but light and heat radiation is reflected.

Due to the hydrophobic character of Parafilm is an ideal temporary storage for individual drops.

From model farmers of the film is used to mask when painting models. These stretches are narrow strips of the material and then allows them to rest for about a minute before to install it. Likewise, an epoxy adhesive point brought by coating in the form and the film after curing are deducted virtually residue-free.

  • Plastic film
  • Laboratory consumables
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