Abstract: A process for the preparation of insect repelling/killing film. The process involves forming a clathrate compound of fenitrothion with cyclodextrin or a starch decomposition product containing cyclodextrin, at the same time granulating said clathrate compound into dry powder, melt-mixing said dry powder with a synthetic material, which is an olefin, soft vinyl chloride, or vinyl acetate plastic, in an amount of 0.1 to 50% (weight ratio), molding said mixture into pellets, and molding said pellets or a mixture of an appropriate amount of said pellets with a synthetic resin material in the form of film.

Abstract: In the case of a process for producing pourable spherical-segment-shaped packing material particles (18) made of plastic which have an external convex and an internal concave surface, the plastic material is mixed with additives, such as bubble forming agents, coloring pigments and similar agents. The plastic material is fed, by means of a feeding funnel (17) into an extruder (14) through an opening in a bush (13) surrounding the extrusion screw. The plastic material plasticizes over the course of the extruder (14) and, because of the difference in speed existing over the cross section of the mass, comes out of an opening (15) in the die with a bent surface. The plastic material is cut off directly at the opening (15) of the die and before any considerable expansion has taken place. Before the processing of the plastic granules in the extruder (14) a bubble-forming agent (nucleation agent) is applied to their surface in a drum (5).

Abstract: Free flowing coated pellets are prepared by blending a first polymer with a second polymer wherein the second polymer is a polymer which has a crystalline or semicrystalline melting point which is at least 10.degree. C. above the melting or softening point of the first polymer, the two polymers being insoluble in one another in the melt state; (2) intimately blending the two polymers; and (3) extruding the blend through a die having an outlet die face which is maintained at a substantially lower temperature than the extruder melt temperature.In its preferred embodiment the first polymer is an elastomer and the second polymer comprises at least one crystalline or semicyrstalline plastic polymer. A typical composition comprises an EPM or EPDM rubber and a mixture of polyethylene and a crystalline copolymer of ethylene and propylene.

Abstract: A process for the production of expandable granules of thermoplastic polymers comprising: (a) the extrusion of the polymer in which an expanding agent is incorporated, through a die-head in order to obtain an expandable polymer; (b) immediate cooling of this polymer in water, kept at a temperature at which the polymer remains in the non-expanded state, but not lower than the Tg of the expandable polymer; (c) cutting of the polymer to granules in water immediately at the outlet of the die-head, and (d) annealing of the thus obtained granules, by slow cooling in a temperature range comprised between at least +5.degree. C. and at least -5.degree. C. the Tg of the expandable polymer, wherein the cooling and the cutting of the polymer to granules and the annealing thereof are carried out under pressure.

Abstract: Disclosed herein are propylene-base random copolymer particles suitable for use in the production of pre-foamed particles. The copolymer particles are obtained by heating starting copolymer particles to the crystallization temperature thereof and then quenching them in a medium of (the crystallization temperature-30.degree. C.) or lower. Processes for obtaining the copolymer particles are also disclosed. Pre-foamed particles produced using the copolymer particles contain large cells. They can thus provide foamed moldings which are substantially free of shrinkage and have good flexibility.

Abstract: The invention relates to plastics granules composed of foamable particles derived from a star-shaped fundamental solid having at least three sides, these particles being a three-dimensionally domed structure by virtue of the sides having paraboloidal curvature, and the surfaces of paraboloidal curvature being staggered in relation to one another. These granule particles preferably have three sides and at least one gap.The invention also relates to a packaging material obtained by foaming the said plastics granules. This packaging material exhibits an improved flow while having at the same time an improved packaging action (good packaging properties and a high void volume).

Abstract: Improved pellets comprising a melt-processable thermotropic liquid crystalline polymer (e.g., a wholly aromatic polyester) are provided. The molten anisotropic melt-forming polymer, while present as a thin film of the specified thickness at an appropriate temperature, is subjected to reduced pressure conditions whereby residual volatiles are evolved and removed, and the polymer thereby is densified to the specified degree prior to pellet formation. The resulting densified polymer next is melt-extruded and is cut to form pellets while at an appropriate temperature. It surprisingly has been found to be of prime importance that the resulting pellets possess a density of at least 95 percent of the theoretical maximum (e.g., a polymer density of approximately 1.35 to 1.4 gram/cc.) if the advantages of the present invention are to be fully realized. These pellets have been found to be capable of undergoing melt processing to form shaped articles having improved physical properties.

Abstract: A machine is provided for forming a supply of jellifiable fluid into jelled spherical droplets by pouring that fluid out of a housing through nozzles while intersecting the path of the fluid with knives rotating in a horizontal plane on a rotated axle. Valves for the nozzles and the rotational speed of the axle are subject to adjustment. A mechanical arrangement is provided for holding all of the valves open to a desired degree against a closing force provided by springs. A jellifying agent is fed through the axle and out onto the knives so that jellification begins to occur immediately as the jellifiable fluid is cut into segments by the rotating knives.

Abstract: Apparatus for cutting thermoplastic filaments or rods with multiple blades in a granulation head of the type which is completely immersed in a cooling liquid, the blades acting with an extrusion die having extrusion orifices arranged in one or more rings centered on the axis of the die and coaxial with a rotary cutting means carrying cutting blades, wherein the cutting blades have an extrados surface inscribed within a regular convex polygon having an apex angle of 7.degree. or less and an intrados surface having a point of inflection situated at a distance between one quarter and one half of the width of the blade, the remainder of the intrados beyond the inflection point having a profile pattern similar to that of the extrados, and methods for chopping thermoplastics with such apparatus.

Abstract: The alignment device or jig is utilized in aligning a shaft of a pelletizer perpendicular with a die face and includes a sensing/scraping assembly which is adapted to travel on a die face and scrape polymer drool off the die face until a scraping edge of the assembly is in constant contact with the die face during rotation of the jig on the shaft of the pelletizer. The scraping edge is mounted on the end of a rod which is spring biased toward the die face and which is axially movable in a bore in the jig and movement of the rod indicates nonperpendicularity of the shaft to the die face. After adjusting the skew of the shaft, cessation of movement of the rod in the bore in the jig will indicate a true perpendicularity of the shaft to the die face.

Abstract: The disclosure relates to a ram extruder including an extruder barrel having an extrusion die at one end and a hydraulic ram at the other end having a piston which is advanced along the barrel by the ram to displace material in the barrel through the extrusion die. To facilitate loading of the barrel a loading port is provided in the side of the barrel adjacent said other end of the barrel through which the barrel may be charged after retraction of the piston following an extrusion operation and a port closure device is provided to close the port after extrusion and evacuate air from the barrel prior to advancing the piston past the port to minimize the air contained in the barrel prior to the extrusion operation.

Abstract: A fire or flame barrier material comprising an ethylene copolymer matrix, 150-220 parts by weight of aluminum hydroxide and 150-220 parts by weight of calcium carbonate or calcium-magnesium carbonate. The material can also include a lubricating agent, an elasticizer, calcium oxide, a polymer softening agent, a color-aging agent, and an antioxidant agent.

Abstract: Vinyl chloride (VC) resins, particularly poly(vinyl chloride) (PVC) and chlorinated poly(vinyl chloride) (CPVC) are reinforced with glass fibers which have been sized with a particular aminosilane coupling agent and an alkylene oxide-containing film former. This combination of sizing components, among all others, generates allylic Cl atoms in the VC chain of the polymer. Though the VC resin contains an adequate amount of stabilizer to counter the formation of such allylic Cl atoms in the mass of the resin, enough are generated near the surface of the glass to cause a reaction with the aminosilane so as to bond the glass fibers to the VC resin so strongly that a composite only fails in coherent failure. The sizing consists essentially of (i) an aminosilane coupling agent having a reactive amine moiety which upon reaction with the VC resin results in a compound having a peak in a proton magnetic resonance spectra at 5.

Abstract: The pelletizer comprises a chamber having a first side and a second side coupled to an extruder. A shaft extends through the first side into the chamber, a rotatable cutter assembly is mounted to the end of the shaft in the chamber and a die assembly is mounted at the second side of the chamber and has a die face facing into the chamber. The cutter assembly is positioned for rotation adjacent the die face. A prime mover is coupled to the shaft for rotating the cutter assembly. Plastic material is extruded through holes in the die assembly into the chamber as the cutter assembly is rotated to cut plastic streams coming out of the die assembly into pellets. A position control assembly automatically controls the position of the cutter assembly adjacent the die face. The cutter assembly has a plurality of cutting blades mounted thereon.

Abstract: There is described herein a method of operating an extruder for thermoplastic material to automatically control the output of the extruder. The extruder includes a kneader screw, a hopper having a feed screw for feeding the thermoplastic material in dry particulate form to the kneader screw and an outlet feed screw for removing the plastic material in molten form from the kneader screw. Each of the screws is operated by a separate electric motor. The method includes monitoring the current of the motor for the kneader screw. Variations in the current indicate variations in the opertion of the kneader screw. Upon any variation in the current of the kneader screw motor, the speed of the hopper feed screw and/or the outlet feed screw is varied to compensate for the variation in the operation of the kneader feed screw and return the current to its original value.

Abstract: A reinforced thermoplastic resin composition comprising a thermoplastic resin, a fibrous, flaky or powdery inorganic reinforcing material, and an uncured, thermally curable resin, such as a thermosetting resin, applied to the surfaces of the inorganic reinforcing material. Molding of this composition by injection molding or the like yields a molded product in which the thermally curable resin has been cured by the heat during the molding to provide a strong chemical bond between the inorganic reinforcing material and the thermoplastic resin. The molded product thus obtained possesses more strength and/or elongation than the conventional thermoplastic resin product.

Abstract: A continuous process for carrying out the process for preparing substantially dust-free thermoset plastic particles from soft plastic mixtures of reactive thermoset plastic-forming materials and volatile components. These soft mixtures which quickly harden after drying are extruded under low pressure and are granulated by cutting while soft. To eliminate excessive amounts of dust the invention uses a premixer and a worm conveyor in a special housing and the conveyor flights are at a low angle of inclination to the horizontal to extrude the soft mixture at low pressure. The soft material at the outlet of the special material is pushed out of the nozzle under a worm rotation which is less than 25 r.p.m. and a pressure is of the order of one pound after which the material is conveyed pneumatically to a cooling station to harden and after cooling is cut into uniform size particles by knives without the formation of dust.

Abstract: A sealable discharge die for thermoplastics, comprising a housing, a dieplate which closes the latter except for perforations for discharge of the plastic melt in strands or filaments, and a perforated plate located immediately below or above this dieplate, one of the plates being slidable or rotatable and the perforated plate having orifices which can be brought into alignment with the perforations of the dieplate.

Abstract: A pipe die for an underwater pelletizer is provided in which a nozzle plate is provided on the surface of a pipe die, the nozzle plate having a hole coaxially with and of the same diameter as a pipe of the pipe die. The nozzle plate is made of a material of the same quality as the die body and is provided with a hardened layer at its cutter side surface. Replacement and repair of the nozzle plate is improved by connecting the same to said die body by bonding the whole junction plane therebetween.

Abstract: An apparatus for controlling extrusion back-pressure in a face cutting apparatus having an extrudate feed means, a die and a cutter is provided. The apparatus consists of a pair of nested dies, one upstream and one downstream, each die having a plurality of areas, each of the areas having a plurality of extrusion orifices. The nested dies are movable relative to another. In one relative position, the orifices of the upstream die exactly aligned with the orifices of the downstream die. Means are provided for relative movement of the dies in response to a change in the pressure adjacent the extrudate delivery end.

Abstract: A method and apparatus of taking a solid, high molecular weight EPM or EPDM polymer into solution in oil as a shear stable viscosity index improver comprising passing the polymer through an extruder at elevated temperature for degradation of the polymer and circulating hot oil across the die face of the extruder while reducing the degraded polymer to particle size upon issuance from the extruder and into the hot oil.

Abstract: Apparatus for forming pellets from extruded strands of thermoplastic material which includes a liquid-filled tank, an extrusion die face disposed beneath the liquid in the tank, at least one knife blade movable in a direction of movement over the die face to cut pellets from at least one strand of material extruded through an orifice communicating with the die face, a wing extending from the knife blade in a direction opposite the direction of movement of the knife blade and defining a space between the wing and the die face, and means for injecting a purge gas into the space to purge the liquid therefrom. Also disclosed is a method of forming pellets from a strand of thermoplastic material extruded below the surface of a quantity of liquid.

Abstract: A centrifugal pelletizer has a hollow electrically and thermally conductive rotor with a series of orifices along its outer rim portion for centrifugally powering strands of heated thermoplastic material from a body of said material in a flowable state within the interior of the rotor. A knife mounted on the frame adjacent the rotor orifices severs the strands into pellets of a predetermined length. A molten material feed tube with fins therein at the exit end to divide the flow extends into a rotor housing to direct flow in a uniform manner to an axially opposite impeller on the rotor and control mechanism, sensitive to the temperature of the rotor adjacent the orifices, controls the supply of current to electromagnets, which have a peripheral magnetic flux conducting plate system extending to and forming a part of the housing creating a flux field which is interrupted by the spinning rotor to induce currents in the rotor which heat it according to the temperature sensed.

Abstract: In the operation of a melter/mixer-gear pump system for processing of synthetic thermoplastic materials, the improvement is disclosed which comprises employing the pressure between the melter/mixer and the gear pump as the controlling parameter which affects, in a proportional relationship, the speed of the gear pump, the energy transmitted to and the consequent temperature of the materials passing through said melter/mixer.

Abstract: A specific class of thermoplastic polymers with improved processability resulting from initial partial degradation of high molecular weight polymers using a chemical prodegradant present in excess of the amount reacted during pelletization. This class of polymers includes polymers and copolymers of polypropylene and butylene. After pelletizing, the polymer including unreacted prodegradant can be safely handled and shipped without difficulty. When remelted by extruding or the like, the prodegradant in the pellets reacts, further reducing the molecular weight as well as narrowing the molecular weight distribution of the polymer to a point where high capacity production of quality fibers and extruded products can be obtained.The prodegradant is preferably of the type that predictably and controllably affects the polymer molecular properties without being significantly affected by minor fluctuations in the polymer producer's or processor's manufacturing steps.

Abstract: In a face cutting apparatus having an extrudate feed means with an extrudate delivery end, a die plate and a cutter, an apparatus and method for controlling extrusion back pressure includes a die having a plurality of extrusion orifices through which a heat plastified material is adapted to be extruded, having a varying orifice density along the length of the die, a pressure sensing device for sensing the pressure adjacent the delivery end and an apparatus for moving the die relative to the delivery end in response to changes in the pressure adjacent the delivery end to align a die area of differing orifice density with the delivery end in order to adjust the flow rate of heat plastified material through the die and the extrusion back pressure.

Abstract: Uniform pellets of thermoplastic material are formed by centrifugally expressing strands of heated material from orifices on the rim of a hollow rotor and severing the strands with a linearly moving endless blade at a selected radial distance from the rim. The severed pellets pass in a tangential path through a cooling spray at the entrance to a pellet outlet duct. The severing blade is mounted on a bracket for movement to and from the severing position and for adjustment radially and circumferentially of the rotor axis. Two blade assemblies are employed alternately so that blade replacement may be accomplished without interrupting operation. Downstream from the outlet duct an auxiliary knife-gate is employed adjacent a scrap duct and is movable from a severing position to a scrap duct closing position.

Abstract: A plastified mass of thermoplastic material containing an expanding agent is extruded and sliced into pieces by shaped cutting edges to produce--on expanding--elements which are shaped in a billowed manner or a double-bubble manner. The billowed elements have an inturned peripheral edge which prevents nesting and interlocking together when used in a shipping container. Similarly, the double bubble elements preclude nesting and interlocking.

Abstract: Granulate-form agglomerates of pulverulent rubber chemicals having a maximum primary grain size of 500 .mu.m , an active substance content of at least 90% by weight and an assessment (a) in the intermixing test of at the most 1.5, (b) in the dust proportion test of at the most 10, (c) in the fine material proportion test of at the most 5 and (d) in the falling test of at the most 70, as well as a process for its production characterized in that the pulverulent rubber chemicals of a maximum primary grain size of 500 .mu.m are mixed with a moistening agent and/or a lubricant and are supplied to a double shaft screw granulator with forced conveyance, in which the spacing between the nozzle plate and the vertically cut screw ends is between 0 and 1.6 mm, whereby the compression ratio K.sub.D is between 1:6 and 1:1.

Abstract: The organic substance present in the form of a melt is cooled below its solidification point in a twin-screw extruder so that it crystallizes out. The crystallized material is then extruded through a breaker plate at the end of the screw extruder and further cooled. It is essential that the temperature prevailing in the screw extruder, its rotational speed and the temperature of the breaker plate should be adjusted such that from 70% to 99.5% and preferably from 95 to 99.5% of the material has solidified by the time it reaches the end of the screw, the non-crystallized liquid residue only crystallizing out during the subsequent cooling operation. Accordingly, a small residue of melt is present during extrusion through the breaker plate. In addition, extrusion is facilitated if the breaker plate is kept at a temperature in the vicinity of the melting point of the material in question.

Abstract: Apparatus is provided for the recovery of dry polymer in porous crumb form in which pellets of polymer containing volatile material from a cutter located at the output end of an extrusion device are conveyed by a first gas stream from the cutter through a first pipe means to a cyclone separator. A second pipe means is supplied with and conveys a second gas stream to the cyclone separator, both the first and second pipe means terminating at and forming an entry to the cyclone separator in which the pellets are cooled and separated from the gas streams and volatile material. The pellets are then removed from the cyclone separator and conveyed to weighing and packaging means.

Abstract: A granulation apparatus in which a conical chamber having a downwardly and outwardly inclined wall is provided for collecting cut granules. The wall is covered with a flowing, circulating film of water, such film being of uniform thickness and circulating quickly. An annular water channel is provided around the cylindrical or conical chamber for collecting the granules, the annular channel being fed through a tangential water inlet. A flat, annular horizontal acceleration chamber is disposed in the upper region of the annular channel and communicates with the channel through an annular aperture formed in the upper radially outward region of the annular channel. At its radially inner periphery the acceleration chamber communicates with the chamber through an annular aperture.The disposition of the inlet, the channel and the acceleration chamber cause water flowing into the chamber to be subjected to centrifugal force whereby the film of water remains closely adjacent the wall and is of uniform thickness.

Abstract: Uniform pellets of thermoplastic material are formed by centrifugally expressing strands of heated material from orifices on the rim of a hollow rotor and severing the strands with a linearly moving endless blade at a selected radial distance from the rim. The severed pellets pass in a tangential path through a cooling spray at the entrance to a pellet outlet duct. The severing blade is mounted on a bracket for movement to and from the severing position and for adjustment radially and circumferentially of the rotor axis. Two blade assemblies are employed alternately so that blade replacement may be accomplished without interrupting operation. Downstream from the outlet duct an auxiliary knife-gate is employed adjacent a scrap duct and is movable from a severing position to a scrap duct closing position.

Abstract: The described process relates to the production of carburizing agents by compacting carbon dusts with a binder, such as hydroxyethyl cellulose, with addition of water and an auxiliary gelling agent. The auxiliary gelling agents used is glyoxal and/or bases of an alkali metal or alkaline earth metal or ammoniacal water. At from 0.5 to 2% by weight the requirement of binder is so small that no noticeable changes in the analytical values for the carbon dust used appear. The molded bodies produced from the compositions are dried at from 20.degree. to 180.degree. C. Calcination is not required.

Abstract: A granulation apparatus which operates in the manner of a water-ring granulator comprises a perforated plate and rotatable cutter tool for granulating material fed through the plate. A recess is provided beneath the perforated plate which is concentric with, but inwardly of, a collection chamber for collecting the granulated material. The recess is dimensioned so as to have a cross-sectional area at least equal to the surface area of the plate.

Abstract: A depositing apparatus for the manufacture of shaped food product includes a hopper having an open top for receiving a prepared mix. Feed rollers positioned within the lower end of the hopper force mix through an extrusion die assembly. The die assembly includes an elongated plate defining a plurality of apertures and supporting a plurality of dies in coaxial relationship with the apertures. A variable restrictor is supported at each of the apertures for varying the effective open area or flow area of the apertures. The flow area may be varied to compensate for variations in weight, consistency or volume of the mix so that relatively uniform weight shapes are deposited onto a conveyor passing underneath the feed hopper. The variable restrictor includes a pair of opposed plates having edges configured in a complementary fashion to the cross-sectional shape of the die. A drive is operably connected to each of the plates so that they may be moved towards and away from each other into the aperture.

Abstract: A pasty mix of granular grits, binder and filler is pressed through a sieve web by rolling action to form cylindrical, worm-like extrusions. After hardening in a heating duct the extrusions are subjected to the same action and thereby granular grit particles are formed each of which contains several grits.The apparatus for carrying out the method includes a sieve web which co-operates with a rotor having several freely rotatable rollers around its periphery.

Abstract: A granulation chamber for plastics materials comprises a top portion effective to be rotated symmetrically about a vertical axis and having a downwardly divergent concave shape, an opening located at the center of the top portion and engaged by an extruder head associated with a star arrangement of granulating knives to be rotated in a horizontal plane intersecting the top portion and a frusto-conical hopper-like bottom portion coupled with the top portion and converging downwardly into a discharge outlet.

Abstract: A method for providing pellets of extrusion compounded expandable polymeric compositions by (a) introducing a blowing agent and polymeric compound into an extruder, (b) extruding a composition containing the blowing agent and polymeric compound with discharge of the extrusion underwater through a pelleter at a temperature below blowing agent activation temperature, (c) supplying a stream of water across the die face of the pelleter at a predetermined first temperature sufficient to produce pellets, (d) supplying additional transport water downstream of the pelleter to further cool the pellets to a second predetermined temperature, and (e) separating the cooled pellets from the transport water. In an additional embodiment collecting the separated pellets, conditioning the transport water to the first predetermined temperature, and recycling the transport water to the die face.

Abstract: An extrusion die of the type particularly suited for use in underwater pelletizing of polymeric materials. The die includes a die body having a forward end face with a plurality of extrusion ports passing therethrough terminating at the forward end face. A layer of insulating material is interposed between the forward end face at the area of the extrusion ports and a subplate which is constructed from the same material as the die body. The subplate is fixedly secured to the die body so as to form a substantially integral relationship therewith. A hardened facing construction is fixedly secured to the outer end face of the subplate. Both the facing and subplate allow communication therethrough with the extrusion ports. The insulating material retards or reduces heat transfer from the heated die body to the cooled facing during an extruding operation.

Abstract: An improved process is provided for rapidly dissolving water-soluble polymer gels in which the gels are subjected to the steps of extrusion, cutting of the extruded gels, forming a slurry of gel particles, subjecting the slurry to high shear forces, and finally mixing the resulting slurry and water to form a dilute aqueous solution of polymer. The improvement comprises cutting of the water-soluble polymer gel, prior to extrusion, into pieces of gel of a size which are small enough to fit into space defined between adjacent flights of the extruder at the feed inlet of the extruder. The process enables dilute aqueous solutions to be prepared on a batch or continuous basis with good reproducibility of polymer concentration in the solution being prepared.

Abstract: An animal litter is prepared by de-watering rejects of a secondary fiber plant, incorporating a deodorant therein, for example, sodium bicarbonate, pelletizing, and drying. The rejects on a dry basis consist essentially of about 50 percent to about 90 percent cellulose and from about 10 percent to about 50 percent fiber making mineral filler, usually kaolin, and sodium bicarbonate is incorporated therein in the amount of between about 1 percent to about 10 percent on the dry basis. Paper broke also may be incorporated.

Abstract: A process for the preparation of shaped bodies includes preparing a plastic mixture of a material selected from the group consisting of aluminum oxides, aluminum hydroxides, silicon oxides, silicon hydroxides and mixtures thereof from a predominantly dry component K1 in powdered form and a paste component K2 comprising water and additional additives, continuously extruding the plastic mixture into cut lengths, shaping the cut lengths into spherical shaped bodies and drying the spherical shaped bodies and optionally tempering such bodies to form catalyst and catalyst supports. The solids content of the powdered component K1 is from 65 to 100% by weight whereas the solids content of the paste component K2 is 10 to 50% by weight. Preferable spherical shaped bodies are based on Al.sub.2 O.sub.3, SiO.sub.2, or Al.sub.2 O.sub.3 /SiO.sub.2.

Abstract: A method of preparing oil-extended elastomer and shoe sole compound as an integral part of the anionic polymerization process for making elastomer is presented. The method eliminates the step of isolating the neat elastomer and of reheating the elastomer to compound it into the final product.

Abstract: Polyolefin resin pellets of greater uniformity of shape and characterized by an almost complete absence of tails are obtained by the use in the pelletizing apparatus of dies which have been coated by a thin layer of finely divided solid lubricant such as molybdenum disulfide or, preferably, graphite applied to the interior surfaces of the die by cross bombardment with a stream or streams of finely divided solid lubricant under pressure.

Abstract: Uniformity of flow rate through an extrusion or pelleting die is provided through each of a plurality of orifices of substantially equal cross sectional area by providing a die in which the length of a narrowed portion of a downstream passageway associated with each orifice is chosen to provide the desired flow characteristics.

Abstract: An annular die for a pelletizing machine, having a multiplicity of radial bores (12) through which in one direction or the other, material is extruded to form pellets, each radial bore (12) having a portion (A) of constant cross-sectional area and a portion (B) of gradually increasing cross-sectional area, the latter extending to the peripheral surface (14) of the die to which material to be extruded is supplied, the transition between the portion (B) of increasing cross-sectional area and the portion (A) of constant cross-sectional area being entirely smooth such that there is no break in the profile of the internal wall surface of the bore (12).

Abstract: A particulate concentrate, for example pellets, is provided comprising predetermined amounts of a pigment and a blowing or foaming agent in a polymer matrix. The concentrate can be added to an extruder together with a polymer insulating material for the formation of color-coded cellular insulation on a conductor wire of a cable, for example a communication cable. The composition of the concentrate is so determined that different color-coded, cellular, insulating coatings can be produced which are dielectrically matched, as required.

Abstract: A conventional underwater plastic pelletizer of the type using a rotatable knife hub is improved by securing to the knife hub a diverter plate for confining the flow of inlet water to the region adjacent the face of the die plate. The cutting knives are mounted on the rotating hub at a rake angle with respect to the hub center and tilted at an angle with respect to the surface of the die plate so as to effectively pull a cut pellet away from an extruded plastic strand, and the die plate is heated by an organic heat exchange fluid. The result is a substantial reduction in orifices frozen off by cooled polymer.

Abstract: A thermally stable, pure transition alumina extrudate suitable for use as a catalyst support has a uniquely defined bimodal pore size distribution and very good mechanical properties. Most of the surface area is in a micropore region having pores of less than 500 Angstrom units, a pore volume of 0.60 to 0.80 cm..sup.3 /g., a narrowly defined effective pore volume distribution within this region and a median pore diameter which can be controlled within the range of 90-210 Angstrom units. The macropore region made of pores having diameters of 1,000- 10,000 Angstrom units has a pore volume of at least 0.10 cm..sup.3 /g. These two pore volumes are essentially connected directly to each other. The extrudates can be strengthened by acidic additives and given increased thermal stability by adding rare earth oxides.