Abstract: Process for producing flexible PVC irrigation pipe by extruding a plasticized PVC composition containing a melt strength-enhancing aid and a chemical blowing agent and (a) the extruded melt being expanded by foaming thereof immediately on leaving the die into a substantially closed-cell extrudate of outer diameter greater than the die orifice with the extrudate surfaces being substantially unpunctured, (b) drawing down the extrudate in the atmosphere causing rupturing of the foam cell walls of the extrudate to form a substantially open-cell extrudate having punctured surfaces, and (c) when the extrudate has been drawn down to a degree which is prior to any cellular collapse which would lead to the formation of water-impervious pipe, cooling the extrudate by passing it through a cooling means in order to prevent said collapse. Preferably the extrudate passes through a tubular guide into a water bath in step (c).

Abstract: A process for the preparation of an alkenyl aromatic polymeric foam body. The process comprising using water-containing organic vegetable matter as a blowing agent in combination with a volatile fluid foaming agent.

Abstract: A method for producing a crosslinked, uniformly expanded article of thermoplastic resin is provided.Thermoplastic resin containing a crosslinking agent and a foaming agent is extruded through a long-land die which is provided with a choking orifice at an end and/or an intermediate portion thereof; a lubricant is provided on the inner surface of the long-land die; the crosslinking agent is decomposed in the long-land die to lower the flow rate of the resin and the foaming agent is decomposed or heated to its boiling point in the long-land die to provide an expandable resin and the crosslinked, expandable resin is then released into an atmospheric or controlled pressure zone to produce the uniform, finely expanded article.

Abstract: A foamed plastic insulator such as an insulated wire having a foamed plastic material insulation layer formed over a conductor. The plastic material includes at least one component having a swelling ratio greater than 55%, and the component comprises at least 20% by weight of the insulation layer. The insulated wire is produced by adding a blowing agent such as a chemical blowing agent and an inert gas and extruding the mixture over a conductor.

Abstract: The invention relates to a process of making articles of foamed polymethyl methacrylate (PMMA). In a first process stage a mixture comprising monomeric methyl methacrylate, plasticizer, preferably liquid foaming agent and catalyst is polymerized by heating and/or irradiation to form a foaming agent-containing solid body. In the second process stage this body is foamed by heating to the softening temperature of the plastic material. Either of these stages may also be performed continuously. The final product is clear-transparent and has large closed cells, a smooth surface, is light- and weather-resistant, readily workable, has good thermal insulation properties also in combination with plastics or glass coatings and may be used in a variety of applications, especially as a transparent insulating slab or plate.

Abstract: A process for producing a film-like or fibrous structure of an aromatic polyester, which comprises(1) forming an unstretched film-like or fibrous structure by melt-shaping a blend comprising 100 parts by weight of (A) an aromatic polyester having a high degree of polymerization derived from an aromatic dicarboxylic acid as a main acid component and an aliphatic diol and/or an alicyclic diol as a main glycol component and (B) 3 to 300 parts by weight of a low-molecular-weight compound being substantially non-reactive with the aromatic polyester (A) and having a boiling point of at least about 200.degree. C.

Abstract: The aim of the invention was to find a method of producing a sorptive body, to be used especially with objectives such as the elimination of odors and air freshening. In the invented process a granular or powdered solid component consisting of a sorptive material, e.g. active carbon, or a compound containing such a material, is mixed with a binding agent, by which it is generally fixed to a carrier substance. The essence of the invention is that at least part of the finely-ground solid component is mixed with a liquid sorbate; only then it is combined with the dissolved binding agent. In a subsequent operation heat is applied to the mixture, thereby expelling the sorbate. The heat causes pores and capillaries to form within the binding agent, thus enabling air to enter into the sorptive substances deposited in the binding agent and so effecting an increase in the active area of the surface of the body.

Abstract: A new process for foaming cellulose acetate rods consists of blending the cellulose acetate with a suitable plasticizer, a nucleating agent, cyclic ethylene carbonate, and a co-reactant for the ethylene carbonate and extruding into a foamed rod. Suitable co-reactants include aromatic diol polyesters, polycarbonates, and poly(ester-carbonates) and monomeric or polymeric materials containing the ##STR1## group, which have melting or flow points of less than about 250.degree. C.

Abstract: A method of continuous upwards production of foamed material by feeding foam forming materials from below and taking foamed material away from above, wherein foaming takes place in diverging expansion enclosure (1) the walls (13, 14) of which are provided with surfaces (15, 17) travelling with the foaming material, which enclosure (1) is defined above by foam already expanded, at the sides by said walls (13, 14) and below by a feed zone for the foam forming materials, and leads into an upwardly directed take off path for the foam.

Abstract: Process and composition for single step production of foam by utilizing a blowing agent, organic peroxide cross linking agent and a silicone block copolymer.

Abstract: Microcellular foam materials having void fractions of about 5 to 30 percent and uniform void sizes on the order of 2 to 25 microns are produced by pre-saturating the material to be processed with a uniform concentration of a gas while controlling temperature and pressure to avoid cell nucleation. Processing is also done under pressure to avoid nucleation. After processing, pressure is released and cell nucleation occurs at or near the glass transition temperature of the material; it is then cooled quickly to preserve the microcellular structure.

Abstract: A process for producing a porous film or sheet, which comprises melt-molding a composition prepared by compounding 100 parts by weight of a polyolefin resin with 25 to 400 parts by weight of a filler and 1 to 100 parts by weight of a liquid or waxy hydrocarbon polymer into film or sheet, and stretching the resulting film or sheet.

Abstract: Disclosed is a process for extruding thermoplastic resinous compositions, comprising the steps of heat plastifying the resinous composition in an extruder; cooling the heat plastified resinous composition exiting from the extruder to a uniform temperature desired for extrusion through an extrusion die, including conveying the resinous composition through at least one enclosed flow path in a cooling device, circulating a cooling medium about the entire circumference of each of the resin flow paths and controlling by the means of orifices the flow of thermoplastic at the inlet and the outlet of the cooling device across substantially the entire cross-section of each of the resin flow paths; and, extruding the cooled thermoplastic resinous composition through an extrusion die downstream of the cooling device.

Abstract: Forming polystyrene foam by extruding polystyrene, nucleating agent, physical blowing agent, and water where the physical blowing agent and water are injected into extruder to provide blowing system. The product produced has small cells at junction points between membranes of the foam.

Abstract: A method and apparatus for preparing a substantially uniform thermoplastic foam extruded from an extruder, the molten thermoplastic resin having uniformly distributed therein a foaming agent. A cooling-mixer continuously receives the extruded mass of resin and foaming agent from the extruder and intimately mixes and substantially cools the mass. A substantially adiabatic zigzag mixer is connected to the cooling-mixer and divides the mass into a plurality of separate streams which are at least partially separated and recombined. A die is connected to the zigzag mixer and extrudes the uniformly cooled mass into a lower pressure zone to produce a substantially uniform thermoplastic foam.

Abstract: An open-cell foamed article of a cross-linked polyolefin having a high open-cell ratio and a high degree of expansion is produced by a method which comprises the steps of preparing a foamable and cross-linkable polyolefin composition, forming the composition into a desired shape maintaining its gel percent at zero, decomposing the cross-linking agent and blowing agent concurrently by heating the composition under atmospheric pressure in such conditions that the peak of the ratio of the degree of cross-linking to the degree of decomposition of the blowing agent is not more than 20 and exerting a mechanical deformation to the resulting polyolefin foam to rupture the cell membranes.

Abstract: The density of the foam is reduced and the thickness of the sheet obtained by extrusion/expansion is increased by grasping the sheet between confining walls which are permeable to gas and movable together with the sheet, and which diverge from each other in the direction of advance of the sheet, and by applying a subatmospheric pressure to the faces of the sheet and through the said walls while the sheet is in its thermoplastic state, after which the foam is gelled by cooling to stabilize the thickness achieved.

Abstract: A process for producing an open cell foam. The process comprises mixing a polyvinyl chloride composition, plasticizer, at least one stabilizer, and a foaming agent to form a blend; gelling the blend; forming the gelled blend into a sheet; and heating the sheet to decompose the foaming agent thereby forming the open cell foam. The sheet formed by the process. The process for forming an intermediate used in the process and the intermediate itself.

Abstract: Method for the preparation of rigid polyvinyl chloride foams with a density of below 200 kg/m.sup.3, in which method rigid polyvinyl chloride which is provided with a melt-flow improver is foamed with a physical blowing agent via an extruder, in which method in a first step, rigid polyvinyl chloride, together with and preferably mixed with 0.1-15 parts by weight per 100 parts by weight of polyvinyl chloride of a melt-flow improver is fed to an extruder and extruded therewith to form a granulate, this granulate is subsequently impregnated, in a second step, with a physical blowing agent and finally, in a third step, the impregnated granulate is fed, to a foaming extruder in which the granulate is extruded while it passes through a temperature profile in which process the rigid polyvinyl is foamed.

Abstract: A method and apparatus for monitoring the average cell size of a plastic foam structure continuously emerging from a production extrusion source which include means and process steps for magnifying an image of an area of a cross-section of said foam structure, developing said image and comparing the cell size of the image with a known standard and controlling production process parameters to obtain a foam structure of predetermined average cell size.

Abstract: The invention provides a novel and improved method for the preparation of a cellular foamed body of a vinyl chloride-based resin having a very fine and uniform cellular structure with high productivity in a continuous process. According to the inventive method, a vinyl chloride-based resin is admixed with a nucleating agent and a foam conditioning resin which is a specified acrylic resin or a styrene-based resin into a resin composition and the resin composition is first heated under pressure to be converted into an at least partly gelled mass, into which a volatilizable foaming agent which is an organic solvent having a boiling point not exceeding 90.degree. C. is injected under pressure so as that the resin composition is uniformly impregnated with the foaming agent. The foaming agent-impregnated and completely gelled resin composition is then brought under a reduced pressure to be expanded into foams with simultaneous cooling.

Abstract: Closed cell phenol-aldehyde foam is prepared by a method which includes a novel frothing and curing technique. An admixture containing a liquid phenol-aldehyde resole resin, a volatile blowing agent, and a surfactant is frothed to produce a stable froth containing closed cells. The cell walls are formed of the liquid resole resin and the closed cells are expanded by the blowing agent in gaseous phase. The froth is formed into an uncured shape and the liquid resole resin is cured to the solid state in the presence of an acid catalyst to produce cured closed cell foam. The internal temperature throughout the shape during curing is above the boiling point of the blowing agent but less than 212.degree. F., and is sufficiently low to prevent further expansion of the shape in an amount to rupture the closed cell walls and thereby form an open cell structure.

Abstract: In a process for producing a plate-like polystyrene resin foam which comprises extruding a molten mixture consisting of a polystyrene resin and a volatile blowing agent by an extruder into a zone having a lower pressure than the inside of the extruder; the improvement wherein said volatile blowing agent is a mixture consisting of dichlorodifluoromethane, ethyl chloride and methyl chloride in which dichlorodifluoromethane accounts for 50 to 70% by weight of the mixture and the remainder consists of ethyl chloride and methyl chloride and the amount of ethyl chloride is at least 30% by weight based on the total amount of ethyl chloride and methyl chloride; and wherein said volatile blowing agent is present in said molten mixture in a proportion of 8 to 17 parts by weight per 100 parts by weight of the polystyrene resin component.

Abstract: The thermally insulated conduit includes an internal pipe, an external pipe, and an insulating foam which fills the interspace formed between these pipes. An electric grid, consisting of a wire heater, extends through the tubular space and is attached to the outer periphery of the internal pipe. The insulating foam used is made from a base of epoxy resins which are polymerized and hardened by an exothermic chemical reaction. The electric grid is used to heat the fluid contained in the internal pipe when the conduit is operated.

Abstract: A process for producing an open cell foam comprising the steps of:(a) forming a compound comprising polyvinyl chloride resin produced by suspension polymerization, at least one organic stabilizer containing at least one Group I metal and at least one organic stabilizer containing at least one Group II metal, at least one surface active agent, and a heat decomposable blowing agent; and(b) heating the compound to decompose the blowing agent thereby producing the foam.A foamable compound comprising polyvinyl chloride resin produced by suspension polymerization, at least one organic stabilizer containing at least one Group I metal and at least one organic stabilizer containing at least one Group II metal, at least one surface active agent, and a heat decomposable blowing agent.The foam formed exhibits high breathability as well as a high water permeability when desired.

Abstract: Composition of matter adapted to be foamed into essentially a closed cell structure, preponderance of the cells being less than 500 microns in size and containing a chlorofluoroalkane of 1 to 2 carbon atoms, said composition comprising chlorinated polyvinyl chloride resin, and effective amount of a blowing agent, an effective amount of a nucleating agent, and 5 to 20 parts of a processing aid per 100 parts of said resin, said processing aid has a dilute solution viscosity of greater than 2.5 and is selected from copolymers of styrene and acrylonitrile containing 10 to 40% of acrylonitrile.

Abstract: An improved foamable dielectric composition comprising a melt extrudable perfluorocarbon resin containing therein (i) a polytetrafluoroethylene (PTFE) nucleating agent and (ii) a volatile blowing agent, preferably a lower fluorocarbon blowing agent having only one or two carbon atoms; a process for forming such a composition; and, products produced therewith. More specifically, a foamed melt extudable fluorinated ethylene-propylene (FEP) polymer containing therein a PTFE nucleating agent and blown to a foamed structure by means of a volatile fluid--e.g., a lower fluorocarbon such as fluoromethane or, preferably, fluoroethane, a process for forming such a foamed composition; and, products produced therewith such as jacketed electrical conductors and/or coaxial cables wherein at least one conductor is bonded to such a foamed melt extrudable resin.

Abstract: Composition of matter that can be foamed to form an expanded product having density of less than 20 lbs/ft.sup.3 and containing a preponderance of the cells in the size range of less than 500 microns comprising a mixture of chlorinated polyvinyl chloride, 5 to 50 parts by weight of the chlorofluoroalkane of 1 to 2 carbon atoms as a primary blowing agent and 0.01 to 2 parts by weight of azodicarbonamide that is dispersed through the resin and forms cell nuclei from which expanded cells are created, all based on 100 parts by weight of the resin.

Abstract: A thermoformed polymeric foam article, such as a cup or container, is disclosed having improved thermal insulation properties. Contact with hot water causes expansion of the foam wall, substantially decreasing foam density and providing greater heat retention.

Abstract: A method for making reticulated foam structure of a crosslinkable thermosetting polymer which includes the steps of dissolving the polymer in a relatively volatile solvent, forming the resultant solution into an emulsion with a relatively less volatile emulsifying vehicle, forming the emulsion into the desired structure, removing the solvent from the structure, removing the vehicle and curing the structure to form a reticulated foam structure.

Abstract: An improved foamable dielectric composition comprising a melt extrudable perfluorocarbon resin containing therein (i) a polytetrafluoroethylene (PTFE) nucleating agent and (ii) a volatile blowing agent, preferably a lower fluorocarbon blowing agent having only one or two carbon atoms; a process for forming such a composition; and, products produced therewith. More specifically, a foamed melt extrudable fluorinated ethylene-propylene (FEP) polymer containing therein a PTFE nucleating agent and blown to a foamed structure by means of a volatile fluid--e.g., a lower fluorocarbon such as fluoromethane or, preferably, fluoroethane, a process for forming such a foamed compostion; and, products produced therewith such as jacketed electrical conductors and/or coaxial cables wherein at least one conductor is bonded to such a foamed melt extrudable resin.

Abstract: The instant invention is directed to a process for the production of microcellular elastomeric moldings comprising:(A) introducing a reaction mixture into a closed mold, said reaction mixture comprising:(i) an organic polyisocyanate,(ii) a hydroxyl group containing compound having a molecular weight of from 1800 to 12,000,(iii) a catalyst for the reaction between hydroxyl groups and isocyanate groups,(iv) an active aromatic diamine having at least one alkyl substituent in the orthoposition to a first amino group and two alkyl substituents in ortho-position to a second group, and(v) air and/or nitrogen dissolved under pressure in any one or more of Components (i), (ii), (iii) or (iv),(B) allowing said reaction mixture to react in said mold and(C) removing the resultant product from said mold, the improvement wherein in any of Components (i), (ii), (iii) or (iv) which does contain said air and/or nitrogen dissolved therein there is included an inorganic, finely divided, nitrogen adsorbing agent in an amount suf

Abstract: A polyolefin filter for tobacco products and the like was prepared. The extruded element is an open-cell foamed polyethylene or polypropylene having a TPM filtration efficiency greater than 20%. The filter rod can be made by extruding polyethylene containing less than 0.2 moles of a volatile blowing agent per 100 grams of resin at a melt temperature between 130.degree. C. and 150.degree. C., the temperature of the die being between 120.degree. C. and 136.degree. C. Higher melt temperature and die temperature are required for polypropylenes.

Abstract: An improved microporous polymer material is made by coagulating, e.g. in water, a polymer solution containing dispersed microscopic particles of a removable filler soluble in a coagulating liquid.

Abstract: The pore size distribution of a microporous separation medium, such as a membrane or gel, is modified so as to provide it with a sharp upper cut-off of preselected molecular size. The modification is effected by first filling the pores of the separation medium with a volatile liquid, and then evaporating a controlled amount of the volatile liquid to form voids at the entrances to the pores. A concentrated solution of a cross-linkable or polymerizable pore-blocking agent, such as a protein, enzyme or polymeric material, is then applied to the surface of the separation medium. The pore-blocking agent is a material which is insoluble in the volatile liquid and whose molecular size distribution has a lower limit corresponding to the preselected molecular size, whereby the pore-blocking agent selectively enters only those pores larger than the preselected size and remains in the voids at the entrances to the pores.

Abstract: A polyolefin filter for tobacco products and the like was prepared. The extruded element is an open-cell foamed polyethylene or polypropylene having a TPM filtration efficiency greater than 20%. The filter rod can be made by extruding polyethylene containing less than 0.2 moles of a volatile blowing agent per 100 grams of resin at a melt temperature between 130.degree. C. and 150.degree. C., the temperature of the die being between 120.degree. C. and 136.degree. C. Higher melt temperature and die temperature are required for polypropylenes.

Abstract: Extruded synthetic resinous thermoplastic foams of increased cell size are obtained when using volatile fluid blowing agents by incorporating a cell-size enlarging agent into the extruded composition, the cell-size enlarging agent being liquid at the foaming temperature and generally soluble in the heat-plastified foamable mixture.

Abstract: Targets for high energy beams, such as laser beams, produced in laser fusion apparatus are described. The targets are porous spheres of deuterated hydrocarbon material, particularly deuterated polyethylene. The spheres are small and have diameters in the range of 50 to 300 microns. Higher neutron yields are obtained from these targets than from solid targets of similar materials, (viz., spherical targets of much higher density). Methods of fabricating the targets by forming them into solid spheres, cross linking their molecules and causing them to swell such that the resultant targets have a microscopically small sponge-like structure, are also described. These micro-sponge targets may be treated by being exposed to tritium gas so as to undergo tritium deuterium exchange which is of enhanced efficiency by virtue of their porous, sponge-like structure.

Abstract: In a process for producing a foamed polyolefin article which comprises melting and mixing a polyolefin, a volatile organic blowing agent, a cell size-controlling agent, and an ester of a long-chain fatty acid and a polyhydric alcohol in an extruder comprising a feed zone, a compression zone and a metering zone, and extruding the resultant molten gel into an area having a lower pressure than the pressure of the inside of the extruder, the improvement wherein said ester is at least one ester of a long-chain fatty acid having 8 to 20 carbon atoms and a polyhydric alcohol having 3 to 6 hydroxyl groups, and said ester is fed in the molten state into the molten gel within the metering zone and mixed with it.

Abstract: This invention relates to a method for a manufacture of plastic sandwich element in which a first extruder is charged with essential ingredients for productions of foamed cellular plastic at a predetermined temperature. A second extruder is charged with essential ingredients for production of solid plastic at a temperature of at least 25 degrees Farenheit below the predetermined temperature. The resulting sandwich is extruded through an extrusion die forming an integral plastic sandwich with the heat of the foamed plastic layer causing a partial melting.

Abstract: An extrusion foamed article with a large cross-sectional area is made by extrusion foaming a mixture of an ionomer resin and a styrenic resin utilizing a volatile blowing agent. The process permits economic production of a novel thick, foamed article having well balanced properties.

Abstract: A method for producing a foamed plastic insulating coating in a wire. A gaseous foaming agent is mix with a resin and passed through a high pressure narrow passage and then through a lower pressure wide passage.The release of pressure, when the resin enters the wide passage, results in a foaming of the resin. The foamed resin is thereafter extruded through an orifice onto a wire. In one embodiment a chemical is added to serve as a nuclei for the gas bubbles formed during foaming. In a second embodiment, a second chemical is added to provide a smoother extruded surface. In still a further embodiment, the pressure in the wide passage is automatically controlled to remain at a predetermined preferred pressure.

Abstract: A method and apparatus are provided for the extrusion of a thermoplastic material in modified form in which the thermoplastic material is introduced into the barrel of a screw extruder, and is heated and forced through the barrel: the material is passed through valve means which together with the temperature of the material is effective to produce a melt transition in the material at a predetermined point and to thoroughly mix the material; subsequently, the material is forced into a low pressure zone in the barrel where a modifying agent is introduced into the material; the resultant mass is forced out of the low pressure zone, and is passed through a mixing means effective to intensify the dispersion of the modifying agent in the mass, the mass is extruded and the extruded material collected.

Abstract: A melt extrusion process for producing a low density open cell filtering element for an aerosol such as tobacco smoke from plasticized cellulose acetate. A mixture of cellulose acetate, plasticized, a volatile liquid blowing agent which is at least a partial solvent for the cellulose acetate and a nucleating agent are melt extruded under conditions wherein the melt is subjected to high shear, the loss of the blowing agent through back flow is prevented, the melt is reduced in temperature prior to extrusion and the extrudate is conditioned in a hot air chamber and then sized in a sizing die.

Abstract: A very low density material is produced by extruding a composition comprising a settable fluid containing long resilient fibres through a narrow die under conditions which cause the extrudate to expand to form an open fibrous structure as it leaves the die, and then causing the fluid to set. This is applicable to both thermoplastic and thermosetting materials. Various coating layers may be applied to provide rigid light-weight panels and shaped articles for various uses including furniture and building applications.

Abstract: The instant invention relates to a process and an apparatus for applying a layer of liquid, foamable reaction mixture to a continuously moving support, such as for the production of foam blocks or foam sandwich panels having a thick foam core.

Abstract: A molding composition is disclosed for forming in a single step a natural sandwich foam product having a cellular core and a thick, densified outer layer. A hard, particulate filler material such as fly ash is admixed with an unreacted, rigid polyurethane foam system, together with a density distribution control agent such as carbon tetrachloride which lowers the viscosity of the admixture. In molding, the mold cavity is charged with the admixture and the foam reaction is permitted to occur with the mold closed. The resultant, filled foam product has a thick outer layer formed adjacent the mold surface of substantially greater density than its core. In the densified layer, both the polyurethane and filler material components of the resultant product are concentrated to provide over three times the density of the core structure. Formulations are set forth which provide substantial layer thickness and an outer surface having a durometer hardness value of 50 or greater over the entire surface area.

Abstract: An improved microporous polymer material is made by coagulating, e.g. in water, a polymer solution containing dispersed microscopic particles of a removable filler soluble in a coagulating liquid.

Abstract: A novel structural member, such as a tennis racket frame, having an unusually high strength to weight ratio is provided comprising an expanded foamed plastic core integrally bonded to a shell comprising at least one layer of resin-coated unidirectionally oriented graphite fibers, the shell completely encasing the core at any transverse cross section of the structural member, said core comprising from about 25 to about 75 volume percent of a low density cellular filler material, such as chopped cork, and from zero to about 60 weight percent of a high density weight control material, such as barium sulfate.

Abstract: Stable foams of reaction resins and/or condensation resins can be obtained by adding a blowing agent which is gaseous under normal conditions to the resin under pressure, the gas liquid interface being enlarged while dispensing with moving equipment, allowing the mixture to expand and to cure.