Electrically conductive foam mouldings

DETAILED DESCRIPTION What we claim is: 1.
A process for making molded electrically conductive foam products which comprises heating polystyrene beads containing a blowing agent to expand the beads to form closed cell polystyrene foam particles, coating said particles by forming a mixture containing a film forming polyacrylate ester and a non-film forming polystyrene dispersion of carbon black whereby a non-continuous coating is produced, placing the partially coated particles in a mold and heating the mold's contents to about 105.
degree.
C.
until the prefoamed beads expand and develop a pressure of about 1 atmosphere gauge in the mold and the beads are welded together.
2.
A process for making electrically conductive foam moldings which comprises mixing prefoamed polystyrene particles containing a blowing agent with an aqueous film forming polyacrylic ester dispension containing carbon black particles and expanding the resulting mixture in a mold to form a foam molding in which the said polystyrene particles are coated with electrically conductive particles and are welded together to form a foam molding.




Description:
The present invention relates to electrically conductive foam mouldings of polystyrene, their use and a process for the manufacture of these foam mouldings.
It is known to employ polystyrene foams, which are manufactured from polystyrene beads containing blowing agent (the beads being commercially available under the name "Styropor") on an extensive scale as packaging materials.
However, for numerous fields of packaging these foam plastics cannot be used, since they generate, or carry, substantial electrostatic charges.
For this reason, numerous materials such as MOS electronic circuits, explosives, plastic lenses and dust-attracting objects must not be brought into contact with Styropor packaging containers.
It is true that so-called "antistatic" grades of Styropor are already commercially available, but these do not exhibit the desired electrical conductivity or neutrality