A paperboard tube is rendered resistant to liquid by coating portions or
all of the tube with submicron-sized particles of inorganic material that
are treated to be hydrophobic and/or oleophobic. The particles can be
applied directly to the paperboard, lodging in surface pores such that the
particles adhere to the paperboard. Alternatively, a light coating of a
tacky binder or adhesive can first be applied to the paperboard and then
the particles can be applied such that they adhere to the binder.
Preferably, the particles have a large surface area per gram; in one
embodiment, for instance, silica particles are employed having a surface
area of about 90-130 m.sup.2 /g. As a result, the particles create a
surface on the paperboard that is highly repellant to liquid.