Abstract: Process for moulding a thermoplastic material by injection onto a rotating core, in which the relative rotation of the various parts of the mould takes place during at least a part of the dwell stage and ends before the end of this stage. This process, which yields good results with polyolefins, makes it possible to manufacture articles such as receptacles and cylinders, exhibiting good mechanical properties.

Abstract: Process for injection moulding on a rotating core of a thermoplastic material exhibiting a modulus of relaxation in shear G.sub.n (7.5) higher than 0.15. This process, which gives good results with polyolefins, makes it possible to manufacture articles such as receptacles and cylinders exhibiting good mechanical properties.

Abstract: Disclosed is a thermoformable composition characterized in that it contains at least one starchy compound, at least one biodegradable polyester and at least one salt of hydroxycarboxylic acid.

Abstract: The invention relates to articles including at least one polyolefin, which are surface-treated and printed with inks for PVC, which are characterized by the surface presence of fluorine and oxygen in concentrations such that the oxygen/carbon atomic ratio (O/C), measured by ESCA spectroscopy at a depth of 1.5 nm, is at least 0.08 and that the fluorine/carbon atomic ratio (F/C) (measured in the same way) has a value of at least 90% of that of the O/C ratio and of not more than 290% of this ratio. It also relates to a process for their manufacture.

Abstract: The invention relates to an alloy composition possessing improved properties of mechanical resistance. The composition contains a starch, which is preferably plasticized, and a polymer which acts as coupling agent which is chosen from the group consisting of polyolefins modified by chemical functional groups which are active toward the hydroxyl functional groups of starch. Generally, the composition also contains a thermoplastic polymer. The invention also relates to the process for preparing this composition and the use of these compositions for the manufacture of films intended for the paper market and for packages made from biodegradable plastic.

Abstract: The invention relates to polymeric compositions comprising at least one polyolefin, at least one thermoplastic starch and at least one ionic compound, the latter being present in a content such that the concentration of anions and of cations in the composition is from 0.002 to 5 mol/kg. It also relates to the master mixture used for the manufacture of these compositions and containing the thermoplastic starch and the ionic compound. The compositions are suitable, in particular, for the production of mono- or multilayer films which can be used, especially, in the paper-making industry.

Abstract: The relationship between the average degree of roughness of the faces of rough appearance, expressed in microns, and the percentage by weight of units derived from vinyl acetate in the copolymer of which the film consists is greater than 0.019.The film is extruded in the form of an extruded sleeve which is cooled in the die by a circulation of a coolant fluid whose temperature T satisfies the relationship: ##EQU1## in which Tc is the temperature at which the Napierian logarithm of the relationship between the length at break and the initial length of a test specimen of the copolymer has a value of 87% of its value at 180.degree.Tm is the mean temperature of the copolymer as it leaves the diea is equal to 0.24G is given by the relationship .rho..times.Cp.times.V.times.H.sup.2 /.lambda..times.Lin which.rho. is the density of the copolymerCp is the specific heat of the copolymerV is the mean flow velocity of the copolymer through the extrusion dieH is the height of the gap between the core and the extrusion die.

Abstract: Means for applying a plastic finishing layer to the surface of a composite article comprising an extruded plastic-based solid body reinforced by one or more bundles of reinforcing fibers, these bundles being affixed to its surface, comprising a ring (1), the entry diameter (2) of which is greater than its exit diameter (3), the internal surface (4) of the said ring furthermore providing a decreasing variation in the internal diameter between its entry and its exit; method of applying a finishing layer, in which method these means are used, and coated composite article.

Abstract: The invention relates to an alloy composition possessing improved properties of mechanical resistance. The composition contains a starch, which is preferably plasticised, and a polymer which acts as coupling agent which is chosen from the group consisting of polyolefins modified by chemical functional groups which are active towards the hydroxyl functional groups of starch.Generally, the composition also contains a thermoplastic polymer.The invention also relates to the process for preparing this composition and the use of these compositions for the manufacture of films intended for the paper market and for packages made from biodegradable plastic.

Abstract: Coextruded granules of coated vinyl acetate/ethylene copolymers consisting of vinyl acetate/ethylene copolymer coated by coextrusion with a polar thermoplastic polymer, such as, for example, poly-(methyl methacrylate) or an ethylene/vinyl acetate copolymer. They are advantageously produced by extrusion drying of a wet coagulate of vinyl acetate/ethylene copolymer to produce a dry, extruded rod, in-line coating of the dry, extruded rod by coextrusion thereof with a polar thermoplastic polymer to produce a coextruded rod, and granulating the coextruded rod. The coextruded granules are not tacky, can be stored without problem, and are useful as coextrusion adhesives.

Abstract: The flexible multilayer structures comprise a layer of vinylidene chloride copolymer bonded to a layer of plasticized vinyl chloride polymer with the aid of a polymeric adhesive consisting of a mixture of vinyl acetate polymer and of polymethyl methacrylate, for which the product of the vinyl acetate weight content, expressed in per cent, multiplied by the dynamic viscosity at 100.degree. C. and 1 s.sup.-1, expressed in kPa s, is greater than 1.3.times.10.sup.3.The flexible multilayer structures may be in the form of films, sheets, cartons or flexible pouches which can be employed in the packaging field.

Abstract: Moulding compositions comprising a polyolefin, cellulose fibres and an unsaturated organosilane exhibiting a tensile elasticity modulus (E), measured at 100.degree. C., higher than 1250 MPa and a ratio G'/G" of their modulus G', representing their elastic response, to their loss modulus G", measured at 200.degree. C. and at a frequency of 0.1 rad/s (0.1 s.sup.-1), with a value of at least 0.80.

Abstract: A mixture is produced, comprising from 50 to 95% by weight of at least one vinyl chloride-based resin, from 1 to 20% by weight of at least one olefin-based resin, from 1 to 20% by weight of a copolymer of ethylene and vinyl acetate which has a vinyl acetate content of between 10 and 35% and from 2 to 40% by weight of a copolymer of ethylene and vinyl acetate which has a vinyl acetate content of between 60 and 95%, and the product thus obtained is then processed.The process makes it possible in particular to produce sheets which have good mechanical properties and which have a remarkable transparency.

Abstract: Structures with multiple polymeric layers comprising a vinylidene fluoride polymer layer bonded to a polar polymer layer by the use of a polymeric adhesive comprising a vinyl acetate polymer. These structures are characterized in that the product of the weight content of vinyl acetate of the polymeric adhesive, expressed in percent, and its dynamic viscosity at 100.degree. C. and 1 s.sup.-1, expressed in kPa s, is greater than 1.4.times.10.sup.3. The structures with multiple polymeric layers can take the form of films, sheets, panels, tubes or hollow bodies which can be employed particularly in the field of protection against corrosion or ultraviolet rays.

Abstract: Biaxially oriented rigid thermoplastic structures with multiple coextruded polymeric layers comprising a layer of vinyl chloride polymer and a coating layer of polymethyl methacrylate containing products absorbing ultraviolet radiation. The content of products absorbing ultraviolet radiation is such that the glass transition temperature of the coating layer does not exceed 105.degree. C., thus permitting an orientation in the range 95.degree.-110.degree. C.

Abstract: The extruded sleeve is cooled at the end of the die by a circulation of a refrigerant fluid whose temperature To satisfies the relationship: ##EQU1## G being equal to: ##EQU2## Tm and V being the mean temperature of the resin at the exit of the die and its mean extrusion velocity,Tc is a temperature characteristic of the extruded resin,.rho., Cp and .lambda. are the density, the specific heat and the thermal conductivity of the resin,H is the height of the die gap in the refrigerated zone,L is the length of the refrigerated zone.

Abstract: The vinylidene fluoride polymer layer is bonded to that of plasticized vinyl chloride polymer by means of a mixture of adhesives consisting of a copolymer of vinyl acetate and of ethylene and of a copolymer of vinyl chloride and of vinyl acetate, the said mixture containing from 36 to 95% by weight of vinyl acetate and exhibiting a dynamic viscosity equal to at least 55 kPa s at 100.degree. C. and 11 s.sup.-1.

Abstract: The flexible thermoplastic structures comprise a vinylidene chloride copolymer layer bonded to a plasticized vinyl chloride polymer layer through the intermediacy of a mixture of polymeric adhesives consisting of 10 to 90 parts by weight of a copolymer of vinyl acetate and ethylene and of 90 to 10 parts by weight of a copolymer of vinyl chloride and vinyl acetate and whose shear elastic modulus G' at 121.degree. C. and 10.sup.-4 cycles/second is greater than 0.5 10.sup.3 Pa.The flexible thermoplastic structures with coextruded polymeric layers may be in the form of films, sheets, tetra-packs or flexible pouches capable of being employed in the packaging field.

Abstract: The thermoplastic structures incorporate an inner vinylidene chloride copolymer layer, each face of which is bonded to a vinyl chloride polymer (2) layer through the intermediacy of a separate intermediary vinyl chloride polymer (1) layer whose gel temperatrue and dynamic viscosity are lower than those of the adjacent vinyl chloride polymer (2).The thermoplastic structures with multiple coextruded polymeric layers may be in the form of sheets, plaques, tubes or rigid or semirigid hollow bodies, which can be employed in the field of packaging.

Abstract: An adjustable feed block for a coextrusion die is provided. The feed block comprises a main central channel for conveying a main stream of molten thermoplastic material towards a coextrusion die, and at least one secondary channel, substantially parallel to the central channel, for conveying a second molten thermoplastic intended to form a local coating layer on the main stream. The downstream end of each secondary channel is inclined relative to the central channel and connected to a portion of the periphery of the said channel. The connection between the central channel and each secondary channel is laterally delimited by the ends of two adjustable slides which can be moved at right angles to the axis of the central channel. These slides make it possible to adjust, during operation, the position and width of the streams of thermoplastic deposited on the main stream.