Abstract: A method of producing a low density polyethylene foam by extruding a melt blend containing polyethylene, an ionomer, a nucleating system and two expanding agents having substantially different vapor pressures and solubility in the melt blend.

Abstract: Shaped articles of organic polymer resins having cellular (foamed) structure are made from heat-expandable normally solid thermoplastic resin compositions in permeable molds particularly characterized by flooding the mold cavity and the expandable material therein with molten salt as heating medium. For example, a permeable mold, charged with pieces of polyethylene containing azobisformamide and crosslinked by electron irradiation, is immersed into a molten salt eutectic mixture of KNO.sub.3, NaNO.sub.2 and NaNO.sub.3 at about 264.degree. C, removed, cooled and washed with water, thereby forming a coherent, unitary cellular resin molded article completely filling the mold cavity.

Abstract: Disclosed is a coaxial cable having greatly improved mechanical and electrical properties derived from a foamed dielectric having a dielectric constant in the range of 1.32 to 1.1, such cable being provided by a novel method of coating a center conductor of the cable with a dielectric with an extruded cellular polyolefin base composition which has been rendered cellular by the direct injection of a blowing agent in a liquid form into the polymer during an extrusion process. Also disclosed is an apparatus and a method of continuous wire electropolishing and pre-coating.

Abstract: Blowing agents comprising urea dicarboxylic acid anhydride do not give rise to discoloring decomposition residues nor form acid or alkaline by-products. These blowing agents may be used for expanding thermoplastic resins.

Abstract: Low density, closed cell, soft foam products having dimensional stability are made from ethylenic resins having low stiffness, especially comprising copolymers consisting essentially of ethylene and monoethylenically unsaturated non-ionic comonomers, by release to lower pressure of a flowable, foamable gel under pressure, e.g., by extrusion foaming, wherein the gel comprises the ethylenic polymer and a volatile mixed blowing agent. The stating polymers are preferably copolymers of ethylene and vinyl acetate having stiffness less than about 20,000 psi. The mixed blowing agents are particularly characterized as mixtures of at least one fluorocarbon constituent I and at least one fluorocarbon constituent II, as defined. Exemplary mixtures contain (I) 1,2-dichloro-1,1,2,2-tetrafluoroethane and (II) from 25 to 50 percent chloropentafluoroethane, octafluoropropane or octafluorocyclobutane based on the mixtures of I and II.

Abstract: A method of producing foamed thermoplastic resin articles having smooth and glossy surfaces free from swirl marks and hair cracks, which comprises melting a thermoplastic resin containing a condensable blowing agent and an organic chemical blowing agent, injecting, in full shot, the molten resin into a mold cavity to which a pressurized gas is being applied during said injection, terminating the application of the pressurized gas to the mold cavity, enlarging the volume in said molded cavity by movement of a mold wall, and thereafter cooling and solidifying the resin to form the foamed articles.

Abstract: A fiber bundle is first formed of entangled fibers by passing fibers through the tapered mole of an extruder, and then the fiber bundle is provided with at least one longitudinal groove which provides an air passage in the final product communication between the ink reservoir and the atmosphere. Subsequently, one end of the fiber bundle with the longitudinal groove is dipped into a liquid urethane prepolymer to form a nib portion by impregnating the dipped portion with the prepolymer. After removal from the liquid prepolymer it is left to stand. During this standing or setting period the reactions among the constituents of the prepolymer and the volatilization of solvent produce a set urethane nib portion having capillary passages therein, and an air passageway where the groove was formed. The fiber bundle thus produced which is called "core portion" of the pen, is machined at its impregnated end to form a nib. Thus, the product consists of a nib material portion and an ink reservoir integral therewith.

Abstract: Stable medium density large cell size styrene polymer foam is extruded in large sections employing as blowing agents: chlorofluoromethane, bromochlorodifluoromethane alone or in admixture with minor quantities of other halogen containing carbon compounds to provide machinable foams of good dimensional stability.

Abstract: A process for the manufacture of a differentially expanded sheet material comprises applying an organic solvent to the surface of an expandable thermoplastic sheet containing a blowing agent and allowing the treated sheet to at least partially dry before a composition containing a metallic powder and a kicker for the blowing agent is applied to selected areas of the treated surface. The sheet is then uniformly heated to a temperature at which the blowing agent in contact with the kicker decomposes but below that at which it decomposes in the absence of the kicker, so that the areas of the sheet in contact with the kicker expand to a greater extent than the uncontacted areas.

Abstract: Self-bonded, balanced nonwoven fibrous fabrics having fibers uniaxially oriented and junction points of biaxially oriented film tissue and fibers in the plane of the fabric, the fibers being primarily oriented in the machine direction with the biaxially oriented film tissue being oriented in the cross direction. The nonwoven fabrics are produced by extruding a molten polymer radially from a circular die, quenching and then drawing the extrudate.

Abstract: An aqueous-alcoholic, foam-growth-controlling printing ink composition having a pH in the range of from about 8 to about 12 of use in the chemical embossing of heat-foamable and expandable resinous materials comprising: (1) from about 1% to about 15% of a foam-growth-controlling chemical agent, such as benzotriazole; (2) from about 1% to about 9% of a water-soluble or water-dispersible alcohol having from 1 to 6 carbon atoms, such as isopropanol; (3) from about 1% to about 11% of a pH controlling or buffering agent, such as ammonia or a water-soluble or water-dispersible alkylaminoalcohol having from 2 to 10 carbon atoms, such as 2-dimethylaminoalcohol, capable of creating or maintaining the pH of the aqueous-alcoholic, foam-growth-controlling printing ink composition in the range of from about 8 to about 12; (4) from about 30% to about 75% of an aqueous printing ink composition; and (5) from about 10% to about 40% of added water, all these percentages being by weight.

Abstract: In a process for rapidly producing a substantially uniform, elongated, cellular thermoplastic article comprising rapidly discharging from a vessel a pressurized gel of a solid thermoplastic amorphous polymer and a gaseous solvent in an amount in the range of from about 25-100% by weight of said polymer, said solvent being capable of forming a flowable gel with the polymer when subjected to superatomospheric pressure, the improvement for shaping the article comprising restraining sufficiently the speed of flow of the gel from the vessel through a die to form the desired shaped article with the gel at ambient temperature in said vessel.

Abstract: Cavities are filled with a foam insulating material by introducing the reaction mixture through the outlet nozzle of a mixing head which is drawn lengthwise through the cavity at a rate adapted to the rate of foaming, wherein the reactivity of the reaction mixture is accelerated during the filling procedure so that the reaction mixture is foaming up simultaneously over the length of the cavity.

Abstract: A method of making nylon (polycarbonamide) foam involving the use of a multi-phase carboxylic acid-containing polymer which reacts with the amine groups of the nylon to produce water which blows the foam during the process.

Abstract: The invention refers to a blowing agent composition consisting of 1,4 butan-diol-bis-(carbonic acid ester-benzoic acid anhydride) and silicon dioxide. Silicon dioxide reduces the decomposition temperature of the anhydride while at the same time increasing the yield of gas substantially.

Abstract: One-shot, flexible polyurethane foams capable of being thermally bonded to various substrates are produced by adding low molecular weight alkylene glycols, glycol ethers, triols, alkanolamine, or polyhydric phenols as modifiers to conventional polyisocyanate foaming mixtures.

Abstract: A process is provided for preparing soft polyvinyl chloride foam by agitating a foamable plastisol at high speed and under pressure.

Abstract: Foam styrene polymer sheet is expanded to form foam products having lower density by a process which includes (a) contacting the foam styrene polymer sheet with an aqueous composition, (b) maintaining the aqueous composition in contact with the sheet to effect impregnation of the sheet by the aqueous composition, and thereafter (c) heating the impregnated sheet to expand the sheet. The expanded products are useful as thermal insulation and packaging material.

Abstract: Method of producing a three-dimensional pattern on a resin article which comprises producing a two-dimensional pattern on a flexible sheet or web of a heat-foamable plastic material, applying heat to cause said plastic material to expand, thus forming a three-dimensional pattern, applying a release coating to the three dimensional surface of said flexible sheet or web, contacting said three-dimensional surface with a resin plastisol, curing said resin plastisol in contact with said surface to form a solid resin object and removing said flexible sheet or web from said cured resin object to expose the three-dimensional pattern thereon.

Abstract: An improved process is provided for producing cigarette filters comprised of a substantially open-cell foamed thermoplastic polypropylene resin wherein a mixture comprising a thermoplastic polypropylene resin, a volatile blowing agent and a nucleating agent is extruded through a die to produce a strand of foamed resin with the strand then being cut into individual filter elements. The improvement comprises employing as a primary nucleating agent from 0.1 to 40 percent by weight, based on the weight of the resin, of a particulate compound of a metal selected from Groups IIA, IIIA or IVA of the Mendeleef periodic table of elements together with from 0.01 to 5.0 percent by weight, based on the weight of the primary nucleating agent, of a synergist consisting of an organic compound having a hydrophobic group and a hydrophilic group. A particularly effective combination is the use of calcium carbonate as the primary nucleating agent and potassium benzoate as the synergist compound.

Abstract: The present invention relates to a method of manufacture of profile-sections of any shape, including complex shapes, of structural foamed thermo-plastic material, having a density of between 0.4 and 0.9 with respect to the corresponding bulk or solid thermo-plastic material, the said method consisting in slowing-down and/or stopping the expansion at the immediate outlet of a conventional extrusion machine, at predetermined zones by blowing or spraying, in a differential manner at the periphery of the extruded product, a fluid at a temperature lower than the softening temperature of the said thermo-plastic material.

Abstract: Expanded styrene polymer sheet material is produced by extruding expandable and/or general purpose styrene polymer with a conventional blowing agent, a nucleating system and small amounts of finely divided hydrophilic silicon dioxide and alkaline earth metal oxide. The resulting product has very fine, uniformly sized pores and improved flexibility.

Abstract: Expanded styrene polymer sheet material is produced by extruding expandable and/or general purpose styrene polymer with a conventional blowing agent, a nucleating system and a small amount of finely divided hydrophobic silicon dioxide. The resulting product has very fine, uniformly sized pores and improved flexibility.

Abstract: An injection molding process for forming cross-linked, foamed moldings of an ethylenic polymer by passing a molding composition comprising an ethylenic polymer/cross-linking agent/foaming agent blend through the cylinder of an injection molding machine without substantially decomposing the cross-linking agent and the foaming agent, introducing the molding composition into a molding composition holding chamber provided at the exit end of the cylinder of the injection molding machine to decompose the cross-linking agent and the foaming agent therein, and injecting the molding composition into a mold.The invention also provides apparatus for carrying out the process comprising an injection molding cylinder for conveying and plasticizing the molding composition and a molding composition holding chamber provided at the exit end of the cylinder.

Abstract: A hard foamed material having a small specific gravity and a high mechanical strength is produced by mixing vinyl chloride resin with a large amount of inorganic powdery substances and a solvent, heating and kneading the resulting mixture in a closed kneader at a given temperature, adding a liquefied butane with a solvent thereto, and heating and foaming the resulting mixture in a mold.

Abstract: Method of producing an entrainer for squeezing or dyeing textile fabric webs with the aid of a foulard which includes inserting a spread-out endless textile web into an annular mold both the web and the annular mold having a periphery and a width corresponding to the periphery and width of the entrainer to be formed and thereafter filling the annular mold with a material that hardens to form a sponge; and endless entrainer produced by the foregoing method.

Abstract: The invention relates to sheet-like plastic packaging particles formed with a normally curved configuration having two spaced apart, curved coextensive surfaces, one of said surfaces being a substantially unfoamed skin and the remainder of said particle including the other surface being foamed, and to methods for producing packaging particles which comprise warped or distorted, foamed sheet particles suitable for use as packaging particles from an extrudable, expandable synthetic plastic material, such as, a polymerized vinyl aromatic monomer, e.g.

Abstract: A continuous process for preparing particulate microporous, open-celled polymer structures in a co-rotating twin-screw processor comprising agitating normally solid organic polymer and chlorofluorocarbon in the melt zone of said processor, cooling the resulting solution under agitation in the cooling and milling zone, extruding a snow-like mass from the cooling and milling zone, and then removing the chlorofluorocarbon from the snow-like mass to leave the polymer structures.

Abstract: Shaped articles comprising a polymeric frame of uniform density having one or more substantially non-foamed skin layers over all, or only a part of, its surface are produced according to the disclosed method which includes forming a foamable mixture of a photopolymerizable ethylenically unsaturated material, such as vinyl acetate, acrylonitrile, unsaturated polyester resins or the like, and a foaming agent therefor in a mould, subjecting part or all of the surface of the mixture retained in the mould to radiation of a wavelength such that photopolymerization of the material occurs forming a non-foamed or non-foamable skin layer or layers. The thus treated foamable mixture is then foamed and the ethylenically unsaturated material in the foam is polymerized. Shaped articles so produced having an open shell structure are also disclosed.

Abstract: A strong, expanded moulded panel or board, having a specific gravity between 0.2 and 0.8, is produced by heating dry urea formaldehyde resin containing 4% to 8% volatile materials in a mould at between 130.degree. and 160.degree. C under light restraining pressure between 30 and 300 psi which permits moderate expansion of the resin owing to the gasification of the volatile materials.

Abstract: A method of producing a lightweight, strong, uniform, foamed layer containing tubular film with good opacity which can be heat-shrunk onto an annular substrate such as a glass bottle rapidly and uniformly is accomplished by co-extruding a low density polyethylene and a mixture of an ethylene polymer and a blowing agent under particular conditions and causing the blowing agent to decompose thereby foaming the ethylene polymer.

Abstract: Typically, injection molded expandable thermoplastics exhibit imperfect surfaces in the form of mottled areas, visible flow lines, and pin holes; these imperfections are caused by the quick chilling of the surface of the expanded thermoplastic as it contacts the mold surface. This invention is a method of injection molding expanded thermoplastics free of these defects by injecting a short-shot of the expandable thermoplastic into an elastic membrane positioned within a cooled mold cavity, containing the short-shot within the membrane until a skin forms on the thermoplastic in contact with the membrane, and then permitting expansion of the thermoplastic in the cavity to form a smooth skin or surface on a substantial portion of the article.

Abstract: An expanded polyvinyl chloride foam is prepared by a process characterized by admixing a polyvinyl chloride resin, which is prepared by emulsion copolymerization of a comonomer having an hydroxyl group, or a group capable of producing an hydroxyl group in the molecule under the processing conditions, with a plasticizer, a cross-linking agent, and a chemical blowing agent, introducing the admixture into a mold at a temperature lower than the melting temperature of said resin, and thereafter heating the resulting molded product to a temperature higher than the melting temperature of said resin to effect foam expansion.

Abstract: Synthetic paper pulp is prepared by extruding a foam sheet of a synthetic thermoplastic fiber forming resin, which resin contains from 0.1 to 5.0 wt. % and preferably from 1 to 2 wt. % of a soap such as aluminum stearate, attenuating the foam sheet as it is extruded and applying either heat or a shearing action to the attenuated sheet to cause it to break down into short fibers containing numerous fibrils. This pulp is then either used directly or blended with natural pulp, wet laid to form a coarse paper and then formed into a final paper product by application of heat and pressure. The soap serves to improve the wettability of the resulting fibers.

Abstract: Foamed thermoset articles are produced by introducing a thermosettable organic resin, a specific class of blowing agents, inorganic particulate filler, and glass fiber in a mold at a given temperature and pressure, and then lowering the mold pressure to a predetermined reduced pressure to cause foaming, and completing the foaming before gelation. The foamed thermoset articles are also disclosed.

Abstract: Improvements in the production of foam form film or sheeting plastic products in order to increase the flexibility characteristics thereof by reducing the size of the voids and increasing the number of voids therein without substantially changing the bulk density, production rate or product size and by reducing the rate at which such foamed products solidify after formation.

Abstract: Foams of mixtures of polyolefins and styrene polymers are produced by mixing the polymers with low-boiling expanding agents in the presence of a hydrogenated styrene/butadiene block polymer or a graft polymer of styrene on a polyolefin at temperatures above the softening point of the polymer mixture and under a pressure which prevents foaming of the mixture, followed by extrusion of the foamable mixture into a zone of lower pressure. The resulting foams are resistant to organic solvents.

Abstract: In manufacturing a foamed structure from an unsaturated polyester resin, a diallyl phthalate resin and a curable 1,2-polybutadiene resin, foaming of the resin is carried out with the reaction of acid esters of phosphoric acid and/or acid esters of phosphorous acid with metal carbonates and/or metal bicarbonates.

Abstract: A polyethylene or polypropylene foam and a method for its manufacture in which polyethylene or polypropylene powder, is mixed with a liquid component, e.g. mineral oil, to a substantially uniform blend and placed in a container such as a closed mold. The mixture is heated to a temperature at which the polymer flows and is in a substantially liquid state such that the intimately mixed polymer and mineral oil enter into a solution, the solution forming in situ in the container. Thereafter, upon further heating, the mineral oil is caused to undergo a phase change from a liquid to a vapor at its boiling temperature, whereupon the mineral oil acts to expand the polymer into a foam. The temperature to which the solution is heated is maintained to less than the temperature at which the polymer foam collapses due to lowering of its viscosity, thereby ensuring that the foam structure is maintained. The foam thus produced is cooled and removed from the mold.

Abstract: A process is disclosed for producing a structural foam article having a surface that reproducibly and faithfully replicates the surface of the mold within which the article was made. The process is an improvement in the "low pressure" process for producing structural foam, wherein the improvement resides in introducing the molten mixture of foamable thermoplastic material and blowing agent into the mold under such conditions that a no-slip boundary condition is maintained at an interface between the flowing thermoplastic and a predetermined portion of the interior surface of the mold, and by maintaining the temperature at said interface at or above a certain temperature (termed "replication temperature"), while the thermoplastic is flowing in the mold.

Abstract: A method of manufacturing foamed moldings having a compartment-structure therein, the average wall thickness of all compartments being at least 0.1 mm, which comprises heating an aggregate of foamable materials, each comprising a layer of plastics or rubber, capable of forming the said compartment wall whereby the foamed materials are bonded with one another at the layer thereof to form an integrated foamed molding.

Abstract: The method of forming, by rotational molding, a foamed polystyrene article that has a continuous covering of thermoplastic material such as low density polyethylene. The method requires the utilization of polystyrene beads that contain substantially less than the maximum possible percentage of blowing or expanding agent. A high temperature, low residence time heating step is found to be adequate for the formation of the article.

Abstract: Pencils made with a resin-based sheath to replace wood sheaths. A sheath material consisting essentially of a resin binder, a fibrous filler and a metallic soap is extruded around a marking core. The resulting extrudate is immediately chilled after leaving the die, and cut into pencil lengths. The apparatus includes core feeding and transport means, core preheating means and chilling means. The resulting pencils possess the physical qualities associated with wood-sheathed pencils due to the fine, closed cell structure of the sheath material. The surface of the sheath is smooth and may be coated with a pigmented resin or painted.

Abstract: A modifier system for extruding PVC foam comprising two separate core-shell polymers, the shells of which are substantially ungrafted to the cores. Also disclosed is an improved process for extruding PVC foam and improved extruded PVC foam composition and articles.

Abstract: A settable foam plastic product being formed in a mold cavity is compressed, after a film has formed on the surface of the product, but before final setting of the product. This compression step, which is carried out by reducing the volume of the mold cavity, has the advantage of increasing the accuracy of reproduction of fine surface detail. The compression step also permits stops to be readily removed to enable subsequent full opening of the mold cavity. This use of movable stops in turn facilitates absorption of the forces encountered during the injection step with less massive machine structure than heretofore, resulting in the possibility of economical manufacture of larger products. The machine also includes an improved mold cavity construction in which the parting planes are perpendicular to the main plane of the product, and incorporating laterally movable end and side mold members to facilitate removal of the product and the formation of surface detail on edge surfaces of the product.

Abstract: A hollow multilayered article is rotationally molded by introducing into the mold particles of a hompolymer or copolymer of ethylene containing a crosslinking agent and heating the mold during rotation thereof to melt this first polymeric layer. Solid particles of a different polymer are then introduced into the mold at a time after at least substantially all of the particles of the first polymer have melted and prior to the time when the inner surface of the first layer would become smooth and glossy. The mold is then rotated and heated to melt the second polymer. The mold is then cooled and the multilayered article removed.

Abstract: A process is provided for the production of a cellular thermoplastic body, wherein solid thermoplastic material is melted under pressure in an extruder, a gaseous blowing agent is injected into the molten thermoplastic material under pressure and said molten thermoplastic material and gaseous blowing agent is passed to a zone of reduced pressure to effect the cellular expansion of said thermoplastic material by said gaseous blowing agent, and wherein said gaseous blowing agent is metered at sonic velocity at a point upstream of the injection of said gaseous blowing agent into said molten thermoplastic material.

Abstract: A product comprising a cellular plastic material is extruded from a modified conventional extrusion head by injecting a gaseous expanding medium into advancing fluent plastic material through porous material forming at least a portion of a section of the core tube in an extrusion chamber. By controlling the interrelationship between various process parameters such as the speed and pressure of the advancing fluent plastic material, the rate of injection of expanding medium into the advancing plastic material, the place where the expanding medium is injected, and the amount the extruded product is allowed to expand before cooling, it is possible to extrude, from a single source of fluent plastic material, a product comprising many different configurations of cellular and solid plastic material such as a uniform cellular structure throughout, or a cellular plastic inner section with a more dense outer covering.

Abstract: Non-woven fabrics are produced from polyolefin foam fibrillated webs. The webs are treated with corona discharge to improve the adhesion thereof when they are laminated under heat and pressure to form a non-woven fabric.

Abstract: a process for the manufacture of a foamed thermoplastic aromatic polyethersulphone comprising heating a solid thermoplastic composition comprising an aromatic polyethersulphone which is not in admixture with another type of thermoplastic polymer, said composition containing 0.25 to 20% by weight of an absorbed volatile liquid selected from water, acetone, ethyl acetate, methyl ethyl ketone, methylene chloride and chloroform, to a temperature above (Tg-50).degree. C where Tg is the glass/rubber transition temperature of the thermoplastic polyethersulphone.Preferably the thermoplastic composition contains 0.5 to 20% and particularly 1 to 20% by weight, of the absorbed volatile liquid.The solid thermoplastic composition may be in the form of a powder or granules so as to produce a foamed puff-ball type of structure or it may be in the form of a shaped article such as a sheet, film, coating, moulding or extrusion so as to produce a foamed shaped article.