FIELD: chemistry.
SUBSTANCE: invention relates to polyester particles having small molecular mass gradient from the surface to the centre for making containers. Described is a particle made from polyester, particularly a homopolymer and copolymer of polyethyleneterephthalate which has characteristic viscosity of not less than 0.70 dl/g, crystallinity degree of at least 15%, acetaldehyde content of 10 parts per million or less and characteristic viscosity on the surface of the particle higher than characteristic viscosity at the centre of the particle by less than 0.25 dl/g, where molecular mass of the particle is increased in solid state. Also described is a method of making a container using the said polyester particles with characteristic viscosity of not less than 0.70 dl/g, involving feeding the particles into an extrusion zone, melting the particles in that zone to form a molten polymer composition and moulding a sheet or a component from the extruded molten polymer.
EFFECT: proposed polyester particle reduces loss of characteristic viscosity compared to traditional granules and enables to carry out the process at low temperature.
48 cl, 3 tbl, 4 ex
