Abstract: A modular plastic pipe formation apparatus to extrude plastic pipe is disclosed and includes a plurality of modules each having a transportable container and at least one component of the pipe formation apparatus located therein. The plurality of modules are aligned in a predetermined manner during formation of plastic pipe with the components aligned for pipe extrusion. The apparatus may also include a closed circuit fluid cooling system to provide cooling fluid to some of modules to cool the pipe being formed, the cooling circuit may flows in a counter direction to the direction of pipe forming in the pipe formation apparatus.

Abstract: In blown film installations, it is known to provide longitudinal stretching of the produced double layer film strip downstream of the draw-off, more precisely downstream of the reversing unit and upstream of the winder. It is also known to stretch the down-drawn film, wherein the film must then be preheated owing to the long cooling path from the draw-off. According to a first feature, the present invention specifies warming the film above the draw-off and then treating it mechanically. The film can thereby be brought with only little energy from a first level of warmth to a temperature level at which it can easily be worked. According to a second feature, the invention specifies providing a tractive force breakdown brake.

Abstract: The present invention relates to a filter medium having improved heat resistance and filtration efficiency.

Abstract: The present invention discloses a process for forming a biaxially oriented film. The process includes first selecting a polyolefin resin wherein said polyolefin resin comprises a linear low density polyethylene resin characterized by having from 9 to 35 weight percent of the total weight of linear low density polyethylene resin eluting from a CEF at a temperature greater than 97.0° C.; and further characterized by having a CDR of from 33 to 80 and a Mw Ratio of from 0.15 to 0.45. Next a film is formed from the polyolefin resin selected in the first step. Finally the film formed in the second step is oriented in a sequential manner. The films produced by this process are characterized by having an ultimate elongation at least 1.5 times greater in the MD as compared to the CD and the 2% secant modulus is a least 1.25 times greater in the CD as compared to the MD.

Abstract: A method for producing a polarizer comprises the steps of: (A) stretching a polyvinyl alcohol-based resin layer to obtain a stretched layer; (B) immersing the stretched layer in a dyeing liquid containing iodine to obtain a dyed layer in which absorbance thereof determined from a tristimulus value Y is from 0.4 to 1.0 (transmittance T=40% to 10%); and (C) removing a part of iodine adsorbed in the dyed layer so that the absorbance of the dyed layer decreases by 0.03 to 0.7, provided that the absorbance of the dyed layer is controlled so that it does not become less than 0.3.

Abstract: A method for producing a polarizer (20) comprises the steps of: (A) stretching a polyvinyl alcohol-based resin layer (10) to obtain a stretched layer (14); (B) immersing the stretched layer (14) in a dyeing liquid (23) containing iodine to obtain a dyed layer (18) in which absorbance thereof determined from a tristimulus value Y is from 0.4 to 1.0 (transmittance T=40% to 10%); and (C) removing a part of iodine adsorbed in the dyed layer (18) so that the absorbance of the dyed layer (18) decreases by 0.03 to 0.7, provided that the absorbance of the dyed layer (18) is controlled so that it does not become less than 0.3.

Abstract: A method for producing a polarizer (20) comprises the steps of: (A) stretching a polyvinyl alcohol-based resin layer (10) to obtain a stretched layer (14); (B) immersing the stretched layer (14) in a dyeing liquid (23) containing iodine to obtain a dyed layer (18) in which absorbance thereof determined from a tristimulus value Y is from 0.4 to 1.0 (transmittance T=40% to 10%); and (C) removing a part of iodine adsorbed in the dyed layer (18) so that the absorbance of the dyed layer (18) decreases by 0.03 to 0.7, provided that the absorbance of the dyed layer (18) is controlled so that it does not become less than 0.3.

Abstract: An extruded air cooled blown film having a) a total thickness of 5 to 500 ?m, b) a mono-layer structure or 2 to 9 coextruded layers, c) at least one layer L containing a polymer selected from the group consisting of polypropylene homopolymers, polypropylene random copolymers, hetero-phasic polypropylene block copolymers, or any mixtures thereof, said polymer having a melt flow rate, according to ASTM D-1238, of 0.1 to 10 dg/min at 230° C. and 2.16 kg, said layer L further containing 0.001 to 2%, relative to the weight of the polymer, of a particular nucleating agent, and optionally d) a Modulus according to EN ISO 527 enhanced by at least 10% versus a reference film without the nucleating agent.

Abstract: A heat-shrinkable polylactic acid (PLA) film and a method of its manufacture are provided. In an exemplary embodiment, the PLA films exhibit heat-induced growth in the cross direction with concomitant shrinkage in the machine direction. The films may comprise any grade of PLA polymer, optionally including additives, such as antiblock, slip, viscosity enhancers and combinations thereof. A method of manufacture is disclosed which includes a post-extrusion temperature conditioning step.

Abstract: The invention relates to an apparatus for treating a multifilament thread in a melt-spinning process, wherein a treatment channel is formed between a housing plate and an impact plate. The housing plate has a nozzle bore which opens into the treatment channel and is connected to a compressed-air connection. Together with the housing plate, the impact plate forms an inlet opening and an outlet opening at both ends of the treatment channel. In order to check the swirling effects which are produced on the thread by the eddying within the treatment channel, according to the invention the impact plate has a thread guiding element in the part piece of the treatment channel between the nozzle bore and the inlet opening, which thread guiding element is configured so as to protrude into the treatment channel in order to deflect the thread.

Abstract: Methods of fabricating a polymeric implantable device with improved fracture toughness through annealing, nucleating agents, or both are disclosed herein. A polymeric construct that is completely amorphous or that has a very low crystallinity is annealed with no or substantially no crystal growth to increase nucleation density. Alternatively, the polymer construct includes nucleating agent. The crystallinity of the polymer construct is increased with a high nucleation density through an increase in temperature, deformation, or both. An implantable medical device, such as a stent, can be fabricated from the polymer construct after the increase in crystallinity.

Abstract: As a first aspect, the present invention is directed to a process for making a heat-shrinkable annular film, comprising: (A) extruding an annular extrudate downward from an annular die; (B) quenching the annular extrudate by applying a quenching liquid to the annular extrudate; (C) reheating the extrudate to an orientation temperature of from 130° F. to 210° F., resulting in a reheated annular extrudate; and (D) orienting the reheated annular extrudate while the reheated annular extrudate is in the solid state, the orientation being carried out with a total orientation factor of at least 2, so that the resulting oriented, heat-shrinkable film has a total free shrink at 185° F. of at least 10 percent. The extrudate comprises at least one semi-crystalline polyamide selected from the group consisting of: (i) polyamide 6, (ii) polyamide 66, (iii) polyamide 6/66, and (iv) polyamide 6/12. The semi-crystalline polyamide makes up at least 5 volume percent of the annular extrudate.

Abstract: An balloon catheter is provided with an improved neck portion. The neck portion of the balloon is used to attach the end of the balloon to a catheter. Before attaching the balloon to the catheter, the neck portion is lengthened and thinned out to make the neck portion more flexible. Heat shrink tubing may be used to apply pressure to the neck portion to force the material of the neck portion to flow along a mandrel inserted into the neck portion.

Abstract: Functionalized porous poly(aryl ether ketone) articles are prepared by reacting ketone groups in the backbone of poly(aryl ether ketone) polymer with a primary amine reagent. Preferred functional primary amines are primary aliphatic amines or substituted hydrazines containing one or more target functional groups including polar groups, such as hydroxyl groups, ˜OH, amino groups, ˜NH2, ˜NHR, ˜NRR?, and ethylene oxide groups, ˜OCH2CH2—, negatively or positively charged ionic groups, such as ˜SO3?, ˜COO?, and ˜NH4+ groups, hydrophobic groups such as siloxane or perfluorcarbone groups, and non-polar groups, such as linear or branched hydrocarbon groups. The functionalized porous poly(aryl ether ketone) article can be prepared by reacting primary amine with a pre-formed, shaped porous poly(aryl ether ketone) article or by functionalizing the surface of a non-porous precursor article that is subsequently converted into a porous article.

Abstract: The preparation and use of novel porous poly(aryl ether) articles is disclosed. The porous articles are prepared from blends of poly(aryl ether) polymers with polyimides by selectively decomposing the polyimide phase. The preferred reagents used to decompose the polyimide phase include monoethanolamine and tetramethylammonium hydroxide. The porous articles can be configured as a single layer or as a multilayer article. The porous articles of the present invention are unique that at least one of the layers exhibits a narrow pore size distribution. The articles of the present invention can be used as a porous media for a broad range of applications, including porous membranes for fluid separations, such as microfiltration, ultrafiltration, and gas separation, as a battery separators, and as a sorption media.

Abstract: Functionalized porous poly(aryl ether ketone) articles are prepared by reacting ketone groups in the backbone of poly(aryl ether ketone) polymer with a primary amine reagent. Preferred functional primary amines are primary aliphatic amines or substituted hydrazines containing one or more target functional groups including polar groups, such as hydroxyl groups, ˜OH, amino groups, ˜NH2, ˜NHR, ˜NRR?, and ethylene oxide groups, ˜OCH2CH2—, negatively or positively charged ionic groups, such as ˜SO3?, ˜COO?, and ˜NH4+ groups, hydrophobic groups such as siloxane or perfluorcarbone groups, and non-polar groups, such as linear or branched hydrocarbon groups. The functionalized porous poly(aryl ether ketone) article can be prepared by reacting primary amine with a pre-formed, shaped porous poly(aryl ether ketone) article or by functionalizing the surface of a non-porous precursor article that is subsequently converted into a porous article.

Abstract: Porous poly(aryl ether ketone) (PAEK) articles are prepared from PAEK/polyimide blends by selective chemical decomposition and subsequent removal of the polyimide phase. Porous PAEK articles exhibit highly interconnected pore structure and a narrow pore size distribution. The porous PAEK articles of the present invention can be utilized as a porous media for a broad range of applications, including membranes for fluid separations, such as microfiltration, ultrafiltration, nanofiltration, and as a sorption media.

Abstract: A blown film process for producing low gauge, latent elastic films with high cross-direction orientation includes preferentially regulating the temperature gradient of the film along the expansion length. The regulation of temperature along the bubble profile allows more effective “down gauging” of the film and improved melt strength of the hot film. The choice of raw materials is an important element in producing cross-direction-oriented, low gauge, latent elastic films. The method of this invention can be carried out as either a multiple-bubble process or a single-bubble process.

Abstract: A new and improved apparatus and method for producing torsion cords comprising the steps of: (1) casting a torsion cord of a rubber composition, the mold having a high pressure resistant cylindrical wall and opposite closed ends, (2) efficiently curing the rubber composition at a moderate temperature and high pressure for an extended period of time in the mold, (3) reducing the pressure in the mold, and (4) removing the molded torsion cord from the mold. An improved torsion cord manufactured by the method of the invention is also provided having closely controlled dimensions and improved physical properties with fewer process control procedures.

Abstract: A porous film is here disclosed which is obtainable by stretching a film in at least uniaxial direction, said film being formed from a resin composition containing 25 to 70 parts by weight of a polyolefin resin and 75 to 30 parts by weight of an inorganic filler; said resin composition further containing 0.5 to 10 parts by weight of dehydrated castor oil (a) and 0.01 to 5 parts by weight of hardened castor oil (b) based on the total 100 parts by weight of the polyolefin resin and the inorganic filler; and the amount of the component (a) being 20 to 95% by weight based on the total amount of the components (a) and (b). In this porous film, softness and feeling like cloth, moisture vapor transmission, uniformity of the film thickness and the like are equal to their conventional levels. Furthermore, the adhesive strength of a securing tape does not deteriorate because the third components (a) and (b) do not float on the surface of the porous film.

Abstract: A film, having two major surfaces, includes an outer layer including a copolymer of ethylene and a C.sub.3 to C.sub.10 alpha olefin, wherein at least one surface has a silicone coating of between 0.1 and 1.2 milligrams per square feet. Multilayer films can also be provided. Films with a combination of good machinability and ink adhesion are obtained. Films with good shrink properties, in combination with good machinability and ink adhesion, are also obtained.

Abstract: An oriented splittable film which contains nylon and meta-xylylene adipamide at a weight ratio of 40-85:15-60 and which was oriented with a magnification above 2.8 times in both directions of MD and TD. Examples of nylon include nylon 66, nylon 6-66 copolymer and so on. Under this manufacturing method for an oriented splittable film, when a raw film is heated in a biaxially orienting process, such as the tubular method, the heating temperature at the side part of the film, in the direction of film width,,when folding the bubbles, is controlled along the circumference direction of the bubbles so that it is lower than the heating temperature of the part of the film which is used later as a product.

Abstract: A method and apparatus for forming an oriented plastic pipe from a plastic tubular material includes a first heated liquid bath for heating the plastic material to the glass transition temperature and a cooled liquid bath downstream of the heated liquid bath for cooling the plastic pipe after orientation of same.

Abstract: A method of manufacturing a monolayer heat-shrinkable, puncture-resistant biaxially oriented film is disclosed. The method includes a double bubble orientation step and extruding a primary tube that includes at least one substantially linear ethylene homopolymer or interpolymer, wherein the substantially linear ethylene homopolymer or interpolymer has an uniform branching distribution, a melt flow ratio I.sub.10 /I.sub.2, .gtoreq.5.63, and a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63, and is also characterized as having essentially no linear polymer fraction, a single DSC melting peak, a density greater than about 0.85 g/cc, and a favorable gas extrusion critical shear rate at the onset of surface melt fracture.

Abstract: A method of manufacturing a multilayer heat-shrinkable, puncture-resistant biaxially oriented film is disclosed. The method includes a double bubble orientation step and extruding a primary tube that includes at least one substantially linear ethylene homopolymer or interpolymer, wherein the substantially linear ethylene homopolymer or interpolymer has an uniform branching distribution, a melt flow ratio, I.sub.10 /I.sub.2,.gtoreq.5.63, and a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63, and is also characterized as having essentially no linear polymer fraction, a single DSC melting peak, a density greater than about 0.85 g/cc, and a favorable gas extrusion critical shear rate at the onset of surface melt fracture.

Abstract: The invention refers to a method for the reduction of the sag and/or of the different stress profile of a flattened tubular film web produced by a blown film process and made of thermo-plastic synthetic resin, transversely to its longitudinal direction. For the solution of the problem to provide a method according to which the sag and/or the different states of tension transversely to the tubular film web can be easily reduced or eliminated to a maximum degree, the tubular film web is heated along its width and then cooled and/or stretched. Furthermore, the invention refers to an apparatus for carrying out the method.

Abstract: A heat-shrinkable polyester tube, which is a tube having heat shrinkability imparted by subjecting an unstretched tube made of a thermoplastic polyester resin to tubular stretching, and which has a crystallinity of not higher than 20% and a shrinkage of more than 5% and not more than 26% in the longitudinal direction (MD) and a shrinkage of at least 25% in the radial direction (TD).

Abstract: A cross-oriented multi-layer laminated plastic film is produced by first providing a flattened tubular plastic film having a outer plastic film layer with a first melting temperature and an inner plastic film layer with a second melting temperature lower than the first melting temperature, the outer plastic film layer having a molecular orientation substantially in the direction of the length of the tubular plastic film. The flattened tubular plastic film is passed from an expanding station in an expanded condition along a predetermined path in the direction of the length of said film to a collapsing station in a continuous manner. The expanded tubular plastic film is rotated about the predetermined path as the film passes from the expanding station to the collapsing station to effect cross-orientation of the outer film layer in directions inclined to the direction of travel of the tubular plastic film.

Abstract: Polymeric, thin oriented films can be made by use of a combination of a hot blown process and a blown bubble process, i.e. a double bubble process. The resulting film has use in replacing PVC for in store stretch wrap applications. Very low density polyethylene, VLDPE, is an especially preferred material for this process. It may be used as a monolayer, or as one layer of a multilayer structure. In practicing the invention, the polymer is extruded and hot blown, and heated to a temperature above its orientation temperature. This heating can be accomplished by the use of a heated liquid reservoir or sock disposed at the lower end of the primary bubble, inside the bubble. The hot blown heated film is then passed through a first set of pinch rolls, re-inflated into a blown bubble, and collapsed at a second set of pinch rolls. Thin, tough and elastic packaging materials are obtained by this process.

Abstract: A method of manufacturing heat-shrinkable, puncture resistant, biaxially stretched thermoplastic films from very low density polyethylene (VLDPE). The film may be entirely VLDPE or it may be multilayer with an oxygen barrier core layer formed of material such as a polyvinylidene chloride copolymer or an ethylene vinyl alcohol copolymer, and two outer layers. One of these outer layers may for example be a blend of ethylene vinyl acetate (EVA) and VLDPE, and the other outer layer may be EVA. The film may be fabricated into bags suitable for packaging food articles such as frozen poultry, primal meat cuts, and processed meat products. The bags have high shrink and improved toughness.

Abstract: A method for treating the surface of a thin porous film material of tetrafluoroethylene resin is disclosed, which comprises heating said surface to a temperature higher than the thermal decomposition point of said resin so as to decompose and remove part of said surface. The resulting thin porous film material of tetrafluoroethylene resin has an adhesive surface while retaining the desired pore size, hardness, and degree of penetration of adhesive.

Abstract: A method for preparing biaxially oriented poly(vinylidene fluoride) films involving the addition of a minor amount of a polymer miscible with PVDF, particularly poly(methyl methacrylate), to the poly(vinylidene fluoride) to form a blend exhibiting reduced crystallinity and reduced rates of crystallization during the film forming process. The low crystallinity permits the blend to be subsequently formed into biaxially oriented film in a double-bubble tubular film extrusion process by retarding the rate of crystallization in the first bubble, thereby permitting formation of the second bubble without rupture. The films thus formed possess piezoelectric and other desirable characteristics.

Abstract: A coextruded, heat shrinkable, thermoplastic multilayer film for packaging fresh red meat cuts and processed meats. The film is produced by coextruding a multilayer structure which includes a first layer comprising very low density polyethylene, a first core layer of vinylidene chloride-methyl acrylate copolymer, and a second layer comprising very low density polyethylene. In another embodiment the first layer is a second core layer confined between said first core layer and a first outer layer comprising a heat sealable thermoplastic polymer or copolymer. In a further embodiment the second layer is a second core layer confined between said first core layer and a second outer layer comprising a thermoplastic polymer or copolymer.

Abstract: A process for preparing a heat shrinkable film which is made from a copolymer of ethylene and 0.5 to 10% by mole of an .alpha.-olefin having 4 to 12 carbon atoms, the copolymer having a g* value (i.e., intrinsic viscosity of the copolymer/intrinsic viscosity of a linear polyethylene having the same molecular weight) of 0.3 to 0.7, a melt index of 0.3 to 2.0 g/10 min., and a density at 25.degree. C. of 0.86 to 0.92 g/cm.sup.3, wherein a tubular film of the copolymer is stretched under the following conditions:(A) the film surface temperature at the starting point of expansion being within the range of 20.degree. to 30.degree. C.

Abstract: Method of manufacturing a heat shrinkable biaxially oriented thermoplastic film by extruding a primary tube including very low density polyethylene (VLDPE), heating the primary tube and biaxially stretching the heated primary tube using a double bubble method to form a tube which is heat shrinkable from about 30% to about 50% in at least one of the transverse and machine directions.

Abstract: A heat-shrinkable, multilayer film suitable for use in fabricating bags for packaging primal and sub-primal meat cuts and processed meats. The multilayer film has a first outer layer of a first ethylene-vinyl acetate copolymer, a core layer of a barrier film including a polyvinylidene chloride vinylchloride copolymer containing between about 70 weight percent and about 90 weight percent vinylidene chloride, and a second outer layer of a second ethylene-vinyl acetate copolymer. The multilayer film is preferably made by co-extrusion of the layers, and then it is biaxially stretched. After biaxial stretching, the multilayer film is irradiated to a dosage level of between 2 megarads and 3 megarads and heat-sealed in the form of a bag. The bag has improved toughness properties and heat-sealing characteristics and is not significantly discolored by the irradiation.

Abstract: The rate for producing blown films of thermoplastic resins may be increased by using the extrusion and blowing apparatus of the invention, which includes a means of rapidly cooling the blown film at points both above and below the bubble frost line.

Abstract: An apparatus for continuously producing a heat-shrinkable crosslinked resin tube from a crosslinkable resin is provided, comprising in successive connection, an extruder head for extruding the resin into a hollow tube, a fluid under pressure being introduced into the interior of the tube being extruded, a crosslinking cylinder disposed downstream of the head for heating the tubular resin for crosslinking, a flare die disposed downstream thereof for allowing the tube to expand under the fluid pressure, a cooling cylinder disposed downstream thereof for cooling the tube, a guide for deforming the tube into a flattened form, and rollers for pressing and drawing the tube away from the extruder head, wherein a smooth interior surface free of a substantial gap or step extends continuously from the crosslinking cylinder to the cooling cylinder.

Abstract: A stretching device for stretching a tubular film includes a mandrel including a stretching section, a pair of payoff nip rolls disposed upstream of the mandrel and a pair of take-up nip rolls disposed downstream of the mandrel. The stretching section of the mandrel is comprised of a plurality of rings arranged substantially concentrically in spaced-apart relationship in the travelling direction of the tubular film. The outside diameter of a ring on the downstream side is larger than that of a ring on the upstream side. Each of the rings has a plurality of rotating members mounted rotatably, and the plurality of rotating members define an outer circumferential ring edge which is generally smoothly circular.

Abstract: Extrusion apparatus for producing a continuous molten tube of a film-forming material includes an extrusion die defining an annular extrusion orifice between adjustable die lips through which a heat-plastified, synthetic, resinous, extrudable film-forming material is extruded in a radial direction. An annular gas bearing in spaced relationship to the orifice redirects the film into a tubular shape. In one die arrangement extrusion takes place radially outward, whereas in a second die arrangement extrusion takes place radially inward.

Abstract: A process of forming biaxially oriented tubular articles by repeatedly performing a cycle of operations which includes engaging a thermoplastic tube by a first clamping member over a first region at a trailing end of the tube and engaging the tube by a second clamping mechanism over a second region at a spacing from the first region so as to define between the clamping mechanisms a portion of the tube to be longitudinally stretched and radially expanded; moving the clamping mechanisms apart to stretch the tube portion therebetween longitudinally; admitting pressure fluid into the tube portion to expand it radially and form a biaxially oriented bubble adjacent the leading end of the tube, and severing a substantial part, but not all, of the bubble from the tube to form the tube with a radially outwardly flared end as the leading end of the tube for the succeeding cycle of operations.

Abstract: A process for producing an air-permeable film is described, comprising stretching in at least one direction a film made of a composition comprising 42 to 87 vol % of a polyolefin resin and 58 to 13 vol % of an inorganic filler and further containing an aliphatic alcohol/fatty acid ester of a fatty acid having 10 to 22 carbon atoms and an aliphatic alcohol having 1 to 12 carbon atoms in an amount of 3 to 25 parts by weight per 100 parts by weight of the above composition.

Abstract: A method of producing biaxially oriented tubular polyetheretherketone films having good optical and mechanical properties and heat resistance, by rapidly quenching at a rate of at least 24.degree. C. per second an unoriented tubular polyetheretherketone film as melt-extruded through a circular die thereby imparting a crystallinity of not greater than 10% to the film, and continuously introducing the thus produced film into the space between a feed nip roll pair and a pull nip roll pair while reheating the film externally to a temperature of 60.degree.-140.degree. C. and allowing the film to expand under the influence of the internal pressure to an areal draw ratio of 4-36, to thereby attain biaxial orientation.

Abstract: An improved method for the production of polyolefin film by extruding molten film from an annular die in a tubular form into an extrusion zone is disclosed wherein physical properties are enhanced by controlling polymeric crystalline growth. The method includes providing a liquid quench medium maintained at a constant temperature range in the extrusion zone immediately adjacent the annular die, extruding the molten film directly into the liquid quench medium, and then orienting the quenched film in a tubular bubble whereby the size and amount of crystalline growth is controlled.

Abstract: A polyacetal copolymer of continuous length is disclosed. The copolymer has an apparent density of 1.20 to 1.46 g/cm.sup.3, and a tensile modulus (X) of 19 GPA or more and a density change percentage (Y) of 85% or more. The relationship between the density change percentage (Y) and the tensile modulus (X) is defined by the following relationship:when 19.ltoreq.X.ltoreq.30, then Y.gtoreq.127.7-1.42X, and when X>30, Y.gtoreq.85.A method for producing this copolymer includes permitting a polymeric material in continuous length to pass through a pressurizing fluid and applying a substantially uniform pressure therearound. A drawing stress is applied to the material while heating it at a temperature not above its softening point, thus subjecting the material to high stretching.

Abstract: A method and apparatus for controlling induced dynamic instability in an axially moving form supported between two axially spaced supports wherein the form is relatively soft and therefore exposed to development of transverse tensional forces tending to pivot the form about one or both supports. Control is effected by establishing a datum axis, repeatedly sensing the lateral position of the form in at least two mutually inclined transverse directions, deriving signals proportional to the sensed lateral displacement of the form from the datum axis, converting the signals to thrust forces, and applying the thrust forces to restore the form to the desired lateral position. The technique is of particular value in the production of oriented polymeric tubular films.

Abstract: A process for producing a thin-walled cylindrical body of an aromatic polyester, which comprises(A) heating a continuous thick-walled tubular body of an aromatic polyester by introducing it continuously into a heating zone while feeding a pressure fluid into the thick-walled tubular body,(B) expanding the heated thick-walled tubular body into a cylindrical form, and(C) continuously stretching and taking up the resulting cylindrical expanded body, while at least forming a fold-free portion in the expanded body in its longitudinal direction; and a thin-walled cylindrical body of an aromatic polyester characterized by a specific intrinsic viscosity, density, wall thickness, surface roughness (CLA), and difference of its refractive indices in the circumferential direction and in a direction perpendicular to the circumferential direction, and substantial freedom from folded marks which cannot be removed at a temperature of 80.degree. C.

Abstract: A three layer heat shrinkable film is disclosed, along with preferred process for making it. The film comprises a first heat sealable layer of an ionomer, a second layer of a vinylidene chloride copolymer, and a third layer of a blend of an ionomer and an EVA copolymer. The EVA content is no greater than 20% of the blend by weight, and the vinyl acetate content is at least 4.5% of the blend by weight. In the preferred process, a three layer tape is coextruded and cooled, and reheated to 197.degree.-203.degree. F., and oriented in a conventional double bubble process.

Abstract: To maintain an air or gas bubble forming in a moving tube of plastics material between pairs of squeeze rollers, an air or gas injecting needle is mounted to pivot substantially in a plane containing the centerline of the tube. The needle pierces the tube wall of the bubble when in one rotary position, moves with the tube while pivoting through an arc depending on the depth of needle penetration and is withdrawn from the bubble in a second rotary position.

Abstract: Long lengths of a heat-shrinkable sleeve for use in splicing electrical cables and the like are made in a continuous process. The sleeve is formed around a permeable core, and the core and sleeve are advanced together in an axial direction, the leading end of the advancing sleeve being hermetically sealed. The core and sleeve pass through a heating station, thereby heating a portion of at least the sleeve, and a fluid is introduced under pressure into the core, thereby internally pressurizing the sleeve to effect a radial expansion of the heated portion thereof. The core and sleeve then pass through a cooling station, thereby cooling the expanded sleeve to stabilize it. A stress graded compound also for use in splicing electrical cables and the like is made by heating a dimethyl silicone liquid to remove entrapped gas and mixing the liquid with a silicone carbide powder having a particle size capable of passing through a 400 mesh screen.