Abstract: A process for treating a lamella-type mineral in the form of particles constituted of stacks of sheets, in order to obtain a functional filler for a polymer material. The mineral is suspended in a liquid with a predetermined initial particle size, after which the suspension is subjected to a delamination procedure in order to separate the sheet from the particles, and obtain a particle size smaller than the initial particle size. The suspension is then subjected to selection in order to eliminate the particles larger in size than the predetermined size; it is subsequently dried, and the mineral particles are treated so as to restrict the creation amongst them of strong irreversible bonds.

Abstract: Method of incorporation a talcum powder into a material, in particular a thermoplastic material. The method consists in (a) mixing the talcum powder with water and a polyethylene glycol, a polypropylene glycol or a copolymer of these compounds, (b) pressing the mixture through dies and sectioning it to obtain granules of an average size exceeding that of the grains of the initial powder, (c) incorporating in the material the product obtained, (d) subjecting the dispersion to mechanical action to break up the granules and to release and distribute in the mass the grains of the initial powder. The invention is characterized by incorporating small particle-sized talcum powders into materials, especially thermoplastic materials, without the practical problem involved in incorporating small particle-sized powders.

Abstract: A reinforced composite tubular body comprises a metallic reinforcement of helical convolutions completely embedded in a tubular body of thermosetting polymer which has a coefficient of elongation at rupture less than 15%. The reinforcement comprises at least one metallic reinforcing strip wound helically around the longitudinal axis of the tubular body so as to form a plurality of successive helical convolutions completely embedded in the wall thickness of the tubular body and separated from one another by the polymeric material. The extent of overlap of adjacent helical convolutions is at least equal to e.multidot..sigma..sub.r /2.tau. where e designates the thickness of the strip, .sigma..sub.r the ultimate breaking strength of the strip and .tau. the shear strength of the metallic strip/polymeric material interface.