Abstract: This invention relates to a rotary kneading screw installed in an extruder for kneading a synthetic resin such as polyester or vinyl chloride with a material such as calcium carbonate, talc, glass fiber or carbon fiber. The rotary kneading screw comprises a plurality of kneading recesses formed along a helical direction, and resin flow passages formed at a helical pitch greater than that of the kneading recesses. These flow passages may cut in a single machining operation to achieve both a reduced operating time and reduced manufacturing cost.

Abstract: This invention relates to a rotary kneading screw installed in an extruder kneading and extrusion-molding a material mixture of a synthetic resin such as polyester resin mixed with one or more of master-batch, calcium carbonate, talc and carbon fiber. Progressively higher pressures are applied to the material mixture passing through a kneading section defined in the rotary screw. This rotary kneading screw is thus capable of kneading and extruding the material mixture in a large amount without deteriorating its physical properties and without lowering fluidity and molecular weight thereof even where the material mixture is difficult to knead.

Abstract: A process for recovering a support from a photographic film is disclosed. The photographic film comprises the support and an undercoating layer provided thereon. The support is made of cellulose triacetate film base. The undercoating layer contains gelatin and cellulose nitrate. According to the present invention, the process comprises the steps of: (I) treating the photographic film with an aqueous solution of a surfactant; and then (II) treating the photographic film with an aqueous solution of a protease to remove the undercoating layer from the support. The aqueous solution of the protease used at the step of (II) preferably further contains an anionic surfactant. It is also preferred that the process further contains the step of (III) treating the recovered support with an aqueous solution of hydrogen peroxide to bleach the support.

Abstract: A rotational screw for mixing synthetic resins with various additives, comprising a plurality of helically arranged mixing recesses provided consecutively, at specified mixing positions, in the peripheral areas thereof and communicated transversely of the helical direction with one another so that the amount of delivered material is large and highly intimate mixing is effected. The improvement comprises a plurality of helically arranged recesses which are triangular in helical cross section, and are arranged to have their corresponding tips of adjacent recesses at 60.degree. angles from each other.

Abstract: The present invention relates to a rotation screw for mixing, for use with an extruder for forming by forcing out a volume of synthetic resin or a mixture of synthetic resin with additives including glass or carbon fiber, calcium carbonate, etc, having a series of centrally situated mixing recesses of large width and a plurality of mixing recesses of small width arranged on both sides of said wide mixing recesses, both of which are helically formed, in specified mixing positions, in the periphery of the rotational screw, arranged in helically adjoined relationship, and partially communicated transversely of the helical direction with one another so that the amount of delivery becomes great and the highly intimate mixing can be effected.

Abstract: This invention is concerned with an improved construction of synthetic resin extruding means provided with a single unit having a kneading power which is strong enough to mix or knead a resin strengthening admixture material with a raw resin material and being able also to extrude nothing but resin from the extruding means as in the case with the conventional type extruding means. The invention further involves a construction of extruding means provided with a particular mouth formed on a kneading portion of the means so that the resin strengthening admixture material can be put into the extruding means.

Abstract: An apparatus for dehydrating synthetic resin pellets comprising a plurality of interconnected truncated conically shaped dehydrating screens disposed vertically with their smaller diameters being uppermost, whereat wet pellets are forcibly directed so that moisture on the surface thereof will be removed by the screens. Blower means are provided for providing upward flowing air to move the wet pellets through the interconnected screens.

Abstract: This invention is concerned with an improved construction of resin pellet producing machine so adapted that a length of resin material extruded in a circular shape through a die of an extruding means is cooled down by a quantity of cooling water jetted forth from a cutter nozzle and at the same time cut continuously to form a plurality of resin pellets thereby to make it unnecessary to appeal further to a cooling water tank.

Abstract: This invention is concerned with a resin material reclaiming machine consisting of a feeding means, dehydrating means and an assorting means thereby to reclaim raw materials of synthetic resin by shredding and cleaning dirty resin or resinated articles used in agricultural pursuits.