Abstract: The invention relates to the preparation of a divided solid composition comprising a talc powder at least a fraction of which consists of grains of talc bonded together in the form of aggregates whose average size is greater than that of said grains of talc. As well as being highly compatible with a large number of thermoplastic resins and having a high talc content, at least of the order of 75%, a divided solid composition obtained according to the invention can be dispersed into fine talc particles in thermoplastic materials during the shaping of these thermoplastic materials (processes with low shear, such as injection moulding, extrusion of sheets/films, etc.) using conventional techniques and equipment. The invention accordingly permits the production of thermoplastic articles loaded with talc without having to use expensive composites (or compounds).

Abstract: The invention relates to a method of making a solid product in a form capable of being handled based on hydrophobic mineral powder such as talcum or mica powder, in particular for cosmetic or hygienic use. This process is characterized in that a hydrophobic mineral powder, particularly based on talcum or mica, is impregnated using a volatile liquid binder in proportions by weight such that the proportion of volatile liquid binder is at least equal to 5% and the proportion of mineral powder at least equal to 80%, and in that the resulting impregnated powder is pressed so as to shape it and to provide it with cohesion ensuring the rigidity of the product. The solid product obtained can take the form of a stick (7) that can be used to ensure a deposit of talcum or mica by contact.

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: The invention relates to talc substances consisting of particles having a sheet structure. These substances are characterised in that each particle has internally the crystalline structure of talc which confers upon it certain specific properties of this mineral (softness, thermal stability) and has hydrophilic surface properties unlike the hydrophobic properties of mineral talc which give rise to useful reactivity. The substances according to the invention have a thermal and chemical stability range similar to that of talc. They can be manufactured by thermal or chemical means under conditions designed to avoid internal conversion of the talc and to effect the surface modifications consisting of replacing inert siloxane bridges by active hydrophilic groups.

Abstract: The invention relates to talc substances consisting of particles having a sheet structure. These substances are characterised in that each particle has internally the crystalline structure of talc which confers upon it certain specific properties of this mineral (softness, thermal stability) and has hydrophilic surface properties unlike the hydrophobic properties of mineral talc which give rise to useful reactivity. The substances according to the invention have a thermal and chemical stability range similar to that of talc. They can be manufactured by thermal or chemical means under conditions designed to avoid internal conversion of the talc and to effect the surface modifications consisting of replacing inert siloxane bridges by active hydrophilic groups.