Abstract: A twin shaft continuous kneading extruder has a twin kneading feeder portion provided with two passages juxtaposed to each other within a casing. The passages are cocoon-shape in cross-section and hold two kneading shafts rotatably disposed in the respective passage portions. A single screw portion substantially extends one of the passages and holds a screw shaft that substantially extends one of the kneading feeder shafts. In addition, a plurality of mixing portions are provided on the twin kneading feeder portion. A first degassing open vent communicates with the kneading feeder shafts between mixing portions while a second vacuum degassing open vent is provided on the single screw portion. The first mixing portion keeps resin fed from a material feeding port in a semi-gelled condition. Thereafter, the resin is completely melted and kneaded in a second mixing portion after degassing. The resin is then fed to the single screw portion which subjects the resin to a vacuum degassing to be further extruded.

Abstract: A biodegradable plastic composition, which may be in the form of a molded dy, includes gelatinized starch and a biodegradable, aliphatic polyester resin having a melting point of 45.degree.-130 .degree. C. The plastic is produced by kneading a blend containing a starchy substance selected from non-gelatinized, granular starch and gelatinized starch and the aliphatic polyester resin at a temperature higher than the melting point of the aliphatic polyester in the presence of water in an amount of 1-45 % based on the weight of the starchy substance.

Abstract: A waste plastic material, e.g. hard plastic waste constituted of vinyl chloride, polyethylene, and foamed polystyrene, soft plastic waste, or other plastic waste containing metal fragments, is immersed in a vegetable or mineral oil heated to 110.degree. to 180.degree. C. for melting in to a saturation of the plastic waste, the proportion of the plastic waste added to the oil being sufficient to saturate the oil. The melted plastic material, in which quantities of the oil are entrapped is mixed with a given dose of a neutralizing agent, e.g. calcium hydroxide, at a temperature of 220.degree. to 300.degree. C. Then, the resultant mixture, in which a quantity of the oil is entrapped is shaped into a solid fuel product, or into a predetermined form disposable in a landfill.

Abstract: A process for producing a resin foam by using an aqueous medium, which comprises(a) treating a resin compound with said aqueous medium to cause the aqueous medium to adhere to and be held by the resin compound, said resin compound being composed of porous agglomerated particles resulting from partial melt-adhesion of thermoplastic resin particles coated with a fine hydrophilic solid powder which does not substantially melt at the melting temperature of the resin particles, said solid powder being embedded in the resin particles but partly exposed at their surfaces,(b) melt-kneading the resin compound treated with the aqueous medium under such an elevated pressure that evaporation of the aqueous medium is substantially inhibited, and(c) thereafter releasing the kneaded resin composition from the pressurized state to foam it; and a thermoplastic resin compound used for the aforesaid process.