Composite thermoplastic material is produced by a screw extruder charged with a mixture of plastics granules and vegetable particles to give the required strength and reinforcement at lower costs

摘要

The composite thermoplastic material has a synthetic polymer matrix and an additive of vegetable material particles. The vegetable particles are added at a rate of 10-50 wt.% of the material, using surface particles of cereal and/or oleaginous origin with a mean size of 1-5 mm. The composite thermoplastic material has a bonding agent in a proportion of 5-25 wt.% of the vegetable particles, using a thermoplastic resin with the same base as the matrix, of transplanted maleic anhydride. The thermoplastic granules have a size of 2-4 mm. The material has a residual moisture of = 1%. An Independent claim is included for a production process, for the composite thermoplastic material, using a screw extruder (10) charged with a thermoplastic and vegetable particles. The material mixture is extruded continuously as a stem (3) from the tapered outlet (20) of the extruder in a homogenous structure. Preferred Features: The granules are fed into the extruder without prior drying. The vegetable particles are formed by granulation and compression into a particle size of 2-6 mm, or by chopping followed by crushing the straw, or they are broken down by sound waves. The vegetable particles are fed into the extruder together with the thermoplastic granules, and any other required additives e.g. bonding agents to give adhesion between the vegetable and plastics granules. The extruder is degassed by suction extraction of moisture from the material mixture being processed. The extruded stem is cooled by an air passage. A further Independent claim is included for a production assembly with a feed station (21) for a dosed delivery of the vegetable particles and a feed station (22) for a dosed delivery of the thermoplastic granules. A further feed station (23) can provide additives. Preferred Features: The screw extruder has an entry (11) for the materials at one end, and a tapered outlet at the other end. A section (14) of the extruder is open to the ambient air, downstream of the entry, followed by a degassing zone (17). The extruded stem is passed through a cooling stage and a cutter to chop it into granules.