Abstract: The invention relates to piezoelectric polymer films.The invention relates to a production process consisting of stretching a polymer material blank by rolling under an electrical field between two oppositely rotating rollers.The invention is more particularly applicable to the production of electromechanical transducers, whose active elements are constituted by piezoelectric polymer films provided with electrodes.

Abstract: Disclosed is a process for producing a multiple-layered sheet of film comprising at least two thermoplastic materials by coextrusion through a slot die, comprising the steps of heat plastifying a first, second, third and fourth thermoplastic material; joining a stream of the first heat plastified thermoplastic material and a stream of the second heat plastified thermoplastic material to form a first combined stream having a generally rectangular cross-section and having an upper layer of the first thermoplastic material and a lower layer of the second thermoplastic material mechnically anchored together by means of profiles formed on the contact surfaces of the two layers; joining a stream of the third heat plastified thermoplastic material and a stream of the fourth heat plastified thermoplastic material to form a similar second combined stream, reducing the width of the first and second combined stream; joining the first and second combined streams in edge-to-edge fashion in a single plane to form a composi

Abstract: A method of producing an extrudate is disclosed in which on-line adjustments are made to size and shape deviations by varying the temperature conditions in the extruder and by varying the relative speeds along the extrusion line. The temperature conditions can be adjusted by varying the temperature of the stock while maintaining a fixed relationship of the die temperature to the stock temperature to produce deviations in the thickness of the extrudate with respect to the width of the extrudate, and by varying the temperature of the die with respect to the temperature in the stock to produce variations in different thicknesses of the extrudate. The relative speeds along the extrusion line can be varied by changing the speed of the screw in a cold-feed extruder, by changing the feed rate for a hot-feed extruder, or by changing the speed of the take-away device which regulates the speed by which the extrudate is taken away from the extruder.

Abstract: In an extruder for making blown tubular film, an extrusion nozzle is divided into equally long segments provided with temperature setting elements. The film thickness is measured over the circumference of the film and film sectors of equal cross-sectional area are allocated to the nozzle segments out of which they were extruded. To produce thick film portions, the associated nozzle segments are cooled accordingly and to produce thin portions the associated nozzle segments are heated accordingly.

Abstract: During the production of a preform of thermoplastic synthetic material by means of extrusion from an extruder head provided with a slot-shaped exit opening, the width of which is changed according to a specific program during the extrusion of the preform in order to change the wall thickness thereof, the wall thickness of at least one section of the preform should be controlled by at least one additional program, which is superposed on at least one portion of the first program, which is longer than the additional program. In this manner, one achieves greater flexibility in respect to fulfilling the requirements of each situation on the programming, namely both in respect to the resolution and in respect to precise determination of the location of the individual switch points, even when a very great number of changes of the slot width must be undertaken over a very short section of the preform or during a very short time period during the extrusion process.

Abstract: A hose construction and method of making same are provided wherein such hose construction comprises a polyolefin tube which has a tubular fluorocarbon barrier layer defining the inner portion of the tube and such barrier layer renders the tube substantially impermeable to the passage of nonpolar hydrocarbons present in the fluid being conveyed through the hose.

Abstract: An extrusion head for use in blow molding machines for molding parison having a single layer or wall or a plurality of layers or walls, in which a plunger is slidably interposed between a head body and a core and the plastic material is successively accumulated in an accumulation chamber defined between the extruding end of the plunger, the head body and the core so that the faster the plastic material is introduced into the extrusion head, the faster it is extruded.

Abstract: An extruder process for blending carbon fiber and tetrafluoroethylene copolymer resins, and laminates from the product of the process.

Abstract: An annular exit die for an extrusion head of the type having a die casing ring and a tapered die core cooperating to form an annular die gap or orifice for fabricating a hollow extrudate of thermoplastic material. The tapered die core is adjustable in the axial direction and changes the radial cross-sectional dimension of the die gap as a function of its position. The casing ring has a lower end and an inner wall defining the outer boundary of the die gap. The wall has a step at the lower end of the ring. The step has an inner radially undulating circumferential profile and a radially undulating edge defining the boundary between the step and the lower end of the casing ring. The inner wall of the ring also has another step disposed radially inwardly of the first-mentioned step. This step has an inner radially symmetrical profile and a radially symmetrical edge defining the boundary between the two steps.

Abstract: Disclosed is a method and apparatus for ensuring uniform distribution of higher and lower viscosity or flow rate resins in a product produced by a coextrusion process. A flow restriction is provided in the flow path of the lower viscosity or flow rate resin to increase the pressure drop of this resin as it passes through a coextrusion die. The increased pressure drop introduced by the flow restriction causes the lower viscosity or flow rate resin to be more uniformly distributed in the extruded product. A specific die construction providing a uniform resin flow channel within the die is also described.

Abstract: A high-strength laminate comprising generally weakly adhered biaxially oriented films, each formed of a blend which exhibits a distinct fibrous morphology with the fibres forming a distinct unidirectional grain when measured on a macro-scale but with the fibre-portions strongly deflected from this direction as seen on a micro-scale, the films being arranged in the laminate such that the unidirectional grain in at least two of the films criss-cross each other. This laminate is produced by melt attenuating the blend(s) while extruding the latter to films, cross-laminating the layers before or after solidification while they are still in molecularly unoriented state--except for the weak orientation produced by the melt-attenuation--and finally strongly biaxially orienting the laminate by stretching in several steps, whereby the stretching is generally uniaxial during each step.

Abstract: An integrally extruded all plastic "pile" weatherstrip comprises an elongated longitudinal substrate from which vertically project a plurality of integral, spaced parallel, thin, flexible, deformable, wavy S-configured fin members. The exposed upper ends of all or any desired lesser number of the fin elements may be partially slit to from 20% to 100% of the fin height to control the amount of air and water moisture infiltration through the weatherstrip. The fin element ends are slit at a desired bias angle with respect to a horizontal line lying within a horizontal plane surface in which the fin ends are located. The extrudable plastic is preferably high density polyethylene, polypropylene or polyvinyl chloride and may optionally contain an ultra-violet absorbent composition and a partially compatible lubricant.

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: In an extruder of the type including an extruding cylinder with an outlet at one end thereof and an extruding screw rotatably disposed in the cylinder and circumferentially formed with a feed flight member for forwarding a plasticized material through the outlet of said cylinder for extrusion through a screen located at the fore end of the extruding cylinder, a screen/diverter changing mechanism including a retainer box fixed to the fore outlet end of the extruding cylinder and internally defining a flow passage of the plasticized material to be extruded; a slide body movable transversely in a guide bore of the retainer box across the flow passage thereof; a screen unit detachably fitted in the slide body and having a screen and a plurality of nozzles; a diverter unit detachably fitted in the slide body and having a diverting flow passage for diverting the flow of the plasticized material from the cylinder; a drive mechanism linked to the slide body for selectively positioning either the screen unit or divert

Abstract: Apparatus for continuously vulcanizing a covered material on a conductor comprises a feed device for feeding the conductor in one direction at a constant speed and an extruder for applying the covered material to the conductor fed from the feed means. A vulcanizing tube extends from the extruder, the cable passing through the vulcanizing tube. The vulcanizing tube has a curing section extending from its inlet to a location intermediate its inlet and outlet. A take-off device is disposed forwardly of the vulcanizing tube for hauling the cable. A load applying device is disposed between the extruder and the take-off device for applying a load to the traveling cable at a location forwardly of the curing section of the vulcanizing tube, so that a tension exerted on the cable in a direction opposite to the direction of travel of the cable is applied to the traveling cable.

Abstract: A process is disclosed for forming blown film of a low strain hardening polymer, such as a low pressure polymerized-low density ethylene copolymer, including an improved film bubble expanding technique which permits high production rates to be achieved with good film bubble stability. Advantageously, most of the films produced by the process have a relatively high degree of film clarity.

Abstract: The present invention relates to laminates comprising a polyvinylidene fluoride resin layer, a thermoplastic resin layer, and an intermediate polyalkyl methacrylate layer and to the method of making such laminates, preferably by coextrusion.

Abstract: An acrylic laminated diffuser panel having a high light-diffusing property is provided, which comprises a laminate of an acrylic resin film having a high light-diffusing property and an acrylic resin plate, wherein the acrylic resin film is integrated with the acrylic resin plate. The acrylic laminated diffuser panel is prepared by laminating the acrylic resin film on the molding surface of at least one of a pair of casting mold parts, casting an acrylic monomer or its partially polymerized product into a space between said pair of casting mold parts, and then, polymerizing the acrylic monomer or the partially polymerized product.

Abstract: The material flow within an extrusion die body is adjusted by a metering device to alter the product perforation pattern of an extrusion product produced in the extrusion die without changes of or modifications to any of the various other parts of the extruder system being required. The extruder system is an apparatus which includes, in addition to a hydraulic cylinder powered press, a basic extrusion die, a die body, a set of perforation forming die pins and a ported cover or pin support plate.

Abstract: An insert is sized for close-fitting reception into either a distribution channel or a standardized receptacle formed in an extrusion coating die to define a distribution channel dedicated to a particular coating fluid.