Abstract: In one aspect the invention provides an energy efficient polymerization method comprising irradiating a polymerizable composition and a photoinitiator with a source of essentially monochromatic radiation where the photoinitiator and the wavelength of the radiation source are selected such that the extinction coefficient of the photoinitiator at the peak wavelength of the source is greater than about 1000 M−1 cm−1 and such that the photoinitiator absorbs at least two percent of the actinic radiation incident on the coating.

Abstract: A method and apparatus for selectively curing a sheet of ethylene-propylene diene termonomer (EPDM) material to form a roofing membrane for installation on a roof deck. The method includes the steps of providing a sheet formed of ethylene-propylene diene termonomer, the sheet having a field and longitudinal edge areas bordering the field; and then simultaneously shielding at least one edge area of the EPDM sheet and exposing at least the field to a source of radiation to cure at least the field of the EPDM sheet and provide a selectively cured EPDM roofing membrane. Also disclosed is the product formed by the method of the present invention.

Abstract: A method for manufacturing a plastic object may include the steps of: (a) providing an injection moulding device with a mould that includes two mould parts which in a closed position define a mould cavity; (b) providing foaming means for causing foaming in the mould cavity of plastic injected into the mould cavity; (c) providing blocking means for temporarily rendering the foaming means effectively inactive; (d) energizing the blocking means; (e) choosing as plastic a mixture of two plastics, wherein the first plastic is a non-type A plastic and the second plastic is a type A plastic that constitutes a maximum of roughly 30 percent by mass of the mixture, wherein the type A plastic is a plastic with high melt strength compatible with the first plastic, for instance HMS PP which is high-melt-strength polypropylene; (f) causing a formed object to cool to a chosen temperature, opening the mould cavity and removing the cooled object.

Abstract: A high molecular weight polyethylene prepared by preliminary polymerization is added at the time of main polymerization of an olefin, for example, propylene, to prepare an olefin (co)polymer composition comprising the above high molecular weight polyethylene finely dispersed as fine particles in the polyolefin, such as polypropylene, and a cross-linked structure is formed in the olefin (co)polymer composition. This process can provide a modified olefin (co)polymer composition improved in the strength in a molten state in terms of melt tension or the like and in crystallization temperature and excellent in moldability such as high-speed producibility, and a molded modified olefin (co)polymer composition excellent in properties such as heat resistance and rigidity.

Abstract: The present invention discloses methods for enhancing the wear-resistance of polymers, the resulting polymers, and in vivo implants made from such polymers. One aspect of this invention presents a method whereby a polymer is irradiated, preferably with gamma radiation, then thermally treated, such as by remelting of annealing. The resulting polymeric composition preferably has its most oxidized surface layer removed. Another aspect of the invention presents a general method for optimizing the wear resistance and desirable physical and/or chemical properties of a polymer by crosslinking and thermally treating it. The resulting polymeric compositions is wear-resistant and may be fabricated into an in vivo implant.

Abstract: Wear resistance and oxidation resistance of polymer material or a polymer component for bioimplantation are improved by packaging a polymer object in a sealed gas impermeable package substantially free of oxygen, irradiating the package with penetrating radiation to an extent sufficient to effect a desired substantial level of cross-linking within the polymer, and warming the packaged object while maintaining an elevated hydrostatic pressure to cause gases released during irradiation to recombine, stabilizing the material against subsequent oxidative change. The pressure stabilization terminates active sites, substantially eliminating free radicals. When applied to finished parts, the process simultaneously hardens and sterilizes the parts without degrading mechanical properties or dimensions. When applied to bulk material or unfinished parts, the part may be subsequent machined or otherwise finished, and sterilized by any conventional means.

Abstract: The present invention relates to pressure-sensitive adhesive compositions. The compositions comprise a poly(1-alkene) pressure-sensitive adhesive component, a non-pressure-sensitive adhesive component, and a radiation-activatable curing agent. The invention further provides pressure-sensitive adhesive tapes and methods for making the compositions and tapes.

Abstract: A medical implant made of polymeric material having an increased oxidation resistance is formed by a method including the step of placing a resin powder in a sealed container. A substantial portion of the oxygen is removed from the sealed container by either a vacuum, an oxygen absorbent or by flushing with inert gas. The container is then repressurized with a gas such as nitrogen, argon, helium or neon so that long term storage may be possible. On use, the resin is transferred to a forming device which both melts and forms the resin in an oxygen reduced atmosphere to produce a polymeric raw material such as a rod or bar stock. The medical implant is then formed from this raw material annealed and sealed in an airtight package in an oxygen reduced atmosphere. The implant is then radiation sterilized and thereafter annealed in the package for a predetermined time and temperature sufficient to form cross-links between any free radicals in neighboring polymeric chains.

Abstract: Optical fiber primary coating systems are disclosed having excellent ribbon stripping and adhesion behavior. The coatings are radiation-curable. The excellent stripping and adhesion behavior can be inner primary coating composition having a slip enhancing component and a high modulus outer primary coating composition. Combination of means can be employed. Stripping behavior can be measured by crack propagation and fiber friction measurements.

Abstract: A process for decomposing a polymer which is capable of undergoing thermal depolymerization to its monomer or monomers, such as for example poly(methylmethacrylate), and for the recovery of at least one of the monomers, includes the steps of subjecting the polymer in solid, gel, partially molten or molten form to microwave heating for a time and at a temperature sufficient to decompose the polymer to produce the monomer or monomers in gaseous, liquid or solid form, without substantial decomposition of the monomer or monomers, and recovering at least one of the monomer or monomers. The monomer or monomers may then be reused for plymerisation.

Abstract: A method for preparing a film suitable for use as the light-modulating unit of an SPD light valve, which film comprises a cross-linked polymer matrix having droplets of a liquid light valve suspension distributed in the cross-linked polymer matrix. The light valve suspension comprises particles suspended in a liquid suspending medium. The method comprises admixing a UV cross-linkable liquid oligomer or polymer and the liquid light valve suspension, emulsifying the resulting admixture to form an emulsion of the liquid light valve suspension in the UV cross-linkable liquid oligomer or polymer, and cross-linking the UV cross-linkable liquid oligomer or polymer while the mixture is in the form of a thin layer of the emulsion by exposing the layer to UV radiation or to an electron beam, such that the film is not damaged due to such exposing. The oligomer or polymer and the particles are free of deleterious effects on one another.

Abstract: The invention relates to a process for heating polymer material, including irradiation of said polymer material with infrared radiation. In accordance with the process according to the invention the infrared radiation has wave lengths which substantially are not equal to the absorption peaks of the polymer material in respect of infrared radiation.

Abstract: A foam article is made by (1) irradiating a propylene polymer material selected from the group consisting of (a) a terpolymer of propylene, ethylene, and butene-1, (b) a polyolefin composition that includes (i) about 31% to about 39% of a copolymer of propylene and ethylene, and (ii) about 58% to about 72% of a terpolymer of propylene, ethylene, and butene-1, and (c) a polyolefin composition that includes (i) about 30% to about 65% of a copolymer of propylene and butene-1, and (ii) about 35% to about 70% of a copolymer of propylene and ethylene, and (2) extruding the irradiated propylene polymer material through a die in the presence of a physical expanding agent and a cell nucleating agent, whereby a structure is formed whose density is at least 10.times. less than the initial density of the propylene polymer material. The foam articles exhibit improved flexibility and low temperature toughness compared to conventional propylene polymer materials.

Abstract: A process for the manufacture of rubber polymerizates comprising the steps of treating said rubber polymerizate with electron beam radiation to adjust the gel content and swelling index of said rubber polymerizate.

Abstract: Chemical reaction is effected utilizing light of an appropriate frequency supplied preferably via optical fibers to one or more light extractors having light-emissive surfaces in contact with reactants. The light can be concentrated before being delivered. Wave guides and a plurality of such extractors can be provided within the vessel.

Abstract: A process for preparing a modified polyalkylene, preferably polyethylene or polypropylene, polymer product is described. The process involves treating the polymer in an impregnation step with UV radiation in the presence of a carbonyl bearing photoinitiator species and a crosslinking species. The radiation may take place in a gaseous or liquid environment which is substantially free of oxygen gas but which comprises at least one of the species.

Abstract: A method for irradiating and modifying high molecular weight organic polymers with high energy radiation so that the radiation impinges only in a distinct pattern which is less than the width of the polymer so as to cause controlled chain scission and continuity in molecular weight distribution. The method improves the flow rate and millability of the polymers.

Abstract: A polymer surface and near surface treatment process produced by irradiation with high energy particle beams. The process is preferably implemented with pulsed ion beams. The process alters the chemical and mechanical properties of the polymer surface in a manner useful for a wide range of commercial applications.

Abstract: The invention relates to adhesive compositions comprising polymers comprising C.sub.6 to C.sub.12 saturated .alpha.-olefin monomers and C.sub.2 to C.sub.5 .alpha.-olefin monomers and an effective amount of photoactive crosslinking agent to crosslink composition upon radiation from a source of actinic radiation.

Abstract: A plate-shaped rubber member consists of at least one rubber mixture. The rubber member has a surface with markings and includes a pre-crosslinked layer directly below the surface at least in the area of the markings. The pre-crosslinked layer is generated by exposure of the surface of the rubber member to electromagnetic radiation or electron beam radiation.

Abstract: A propylene homopolymer having a stick-point of 30 cm or less during melt spinning, an oligomer content of less than 1500 ppm without postpolymerization treatment to remove oligomers, and a melt flow rate greater than 300 dg/min is prepared by radiation visbreaking in a multistage fluidized bed reactor. The polymer is subjected to irradiation in the substantial absence of oxygen, followed by a multistage treatment in the presence of a controlled amount of oxygen. The radiation visbreaking process can also be applied to other propylene polymer materials. The propylene polymer materials produced by this radiation visbreaking process can be used, for example, for extrusion coating, film production, and injection molding.

Abstract: A graft copolymer of a propylene polymer material is prepared by (1) making an oxidized propylene polymer material by (a) irradiating a porous particulate propylene polymer material in the substantial absence of oxygen, (b) exposing the irradiated propylene polymer material to a controlled amount of oxygen of greater than 0.004% but less than 15% by volume at a temperature of 40.degree. C. to 110.degree. C., and (c) heating the irradiated polymer material to a temperature of at least 110.degree. C. in the presence of a controlled amount of oxygen within the same range as is used in the previous step, (2) dispersing the resulting oxidized propylene polymer material in water in the presence of a surfactant at a temperature of 30.degree. C.-90.degree. C., (3) adding (a) a primary reducing agent, (b) a chelating agent, and (c) a secondary reducing agent, (4) adding at least one vinyl monomer, and (5) recovering the graft copolymer from the reaction mixture.

Abstract: A process for producing a polymer which can be used as a powder coating material or a hot-melt adhesive in which at least one polyolefin is subjected to a low-temperature plasma treatment with frequencies changing during the treatment in a frequency range of from 30 kHz to 10 GHz.

Abstract: A method of improving heat-seals for polyolefin polymers which are coated onto a paperboard substrate. The method obviates the need for use of a curable bonding agent. The materials are exposed to high energy radiation prior to formation of the heat seal to induce crosslinking of the poller and thereby increase the average molecular weight of same.

Abstract: Only an outer surface of an unvulcanized rubber sheet is preliminarily crosslinked by irradiating an infrared ray or a far infrared ray to the unvulcanized rubber sheet prior to subsequent final vulcanization, whereby the occurrence of rubber spew and rubber flash is considerably suppressed at the vulcanization step.

Abstract: Disclosed are graft copolymers of polyolefins and a method of preparing the graft copolymers. The method includes irradiating a mass of olefin polymer particles and thereafter treating the mass of particles with a vinyl monomer in liquid form. A nonoxidizing environment is maintained throughout the process while free radicals produced in the olefin polymer by the irradiation are present, thereby preventing degradation of the polymer. In a final step, residual free radicals are deactivated, and any unreacted monomer is removed.

Abstract: A high molecular weight compound having a number average molecular weight of 5,000 to 30,000 formed from a styrenic or acrylic monomer chain and a rubber chain which are attached as block or graft polymers. A photopolymerizable resin composition includes a copolymer having a number average molecular weight of 5,000 to 30,000. The copolymer has a styrenic or acrylic monomer chain and a rubber chain attached in block or graft form.

Abstract: Disclosed is a normally solid, high molecular weight, non-linear, substantially gel-free, propylene polymer material characterized by high melt strength due to strain hardening which is believed to be caused by free-end long chain branches of the molecular chains forming the polymer.Also disclosed is a process for making the polymer by high energy radiation of a normally solid, high molecular weight, linear, propylene polymer in a reduced active oxygen environment, maintaining the irradiated material in such environment for a specific period of time, and then deactivating free radicals in the material.Further disclosed is the use of the strain hardening polymer in extensional flow operations such as, for example, extrusion coating, film production, foaming and thermoforming.

Abstract: Disclosed is a normally solid, high molecular weight, gel-free, amorphous to predominantly crystalline, propylene polymer characterized by high melt strength due to strain hardening which is believed to be caused by free-end long chain branches of the molecular chains forming the polymer.Also disclosed is a process for making the polymer by high energy radiation of a normally solid, high molecular weight, linear, propylene polymer in a reduced active oxygen environment, maintaining the irradiated material in such environment for a specific period of time, and then deactivating free radicals in the material.Further disclosed is the use of the strain hardening polymer in extensional flow operations such as, for example, extrusion coating, film production, and thermoforming.

Abstract: A polyolefin composition, which comprises: (A) 1 to 99% by weight of a polyolefin in having the following properties of (a) to (e); (a) a ratio of kinematic viscosity .eta..sub.1 at a frequency of 10.sup.-1 rad/sec to kinematic viscosity .eta..sub.2 at a frequency of 10 rad/sec at a temperature of 190.degree. C. according to a kinematic viscoelasticity determination method of 4 to 20, (b) a crystallization peak temperature Tcp according to a Differential Scanning Calorimetry of 110.degree. to 130.degree. C., (c) a ratio (Tmp/Tcp) of melting peak temperature Tmp to crystallization peak temperature Tcp according to a Differential Scanning Calorimetry of 1.1 to 1.5, (d) Tmp/(Tmp-Tcp)=3.0 to 9.8, and (e) a crystal structure exhibiting a-axial orientation in a diffraction pattern according to a X-ray diffraction method, and (B) 99 to 1% by weight of a propylene resin having the following properties of (f) and (g); (f) a ratio of kinematic viscosity .eta..sub.1 at a frequency of 10.sup.

Abstract: Compositions radiation-curable to pressure sensitive adhesives comprise (1) one or more copolymers of .alpha.-olefins of which 90.1 to 99 mole percent are one or more straight chain .alpha.-olefins, having 2 to 10 carbon atoms of which at least 55% have 6 to 10 carbon atoms, and 9.9 to 0.1 mole percent are one or more .alpha.-olefins having 6 to 20 carbon atoms and at least one methylidyne group; (2) an effective amount of a photoactive hydrogen abstracting agent; and, optionally, (3) a tackifying resin. The compositions, on exposure to radiation, provide adhesive films useful in adhesive applications, especially where a bonded article is to be used at elevated temperatures.

Abstract: Disclosed is a normally solid, high molecular weight, gel-free, amorphous to predominantly crystalline, propylene polymer characterized by high melt strength due to strain hardening which is believed to be caused by free-end long chain branches of the molecular chains forming the polymer.Also disclosed is a process for making the polymer by high energy radiation of a normally solid, high molecular weight, linear, propylene polymer in a reduced active oxygen environment, maintaining the irradiated material in such environment for a specific period of time, and then deactivating free radicals in the material.Further disclosed is the use of the strain hardening polymer in extensional flow operations such as, for example, extrusion coating, film production, and thermoforming.

Abstract: A normally solid, high molecular weight, gel-free, irradiated ethylene polymer is characterized by high melt strength due to strain hardening elongational viscosity, which is believed to be caused by free-end long chain branching of the molecular chains forming the polymer. The polymer is prepared by (1) irradiating a normally solid, high molecular weight ethylene polymer without strain hardening elongational viscosity while in the solid state in an environment in which the active oxygen concentration is less than 15% by volume, maintaining the irradiated material in this environment while in the solid state for a specific period of time, and then deactivating free radicals present in the material.

Abstract: Disclosed is a normally solid, high molecular weight, non-linear, substantially gel-free, propylene polymer material characterized by high melt strength due to strain hardening which is believed to be caused by free-end long chain branches of the molecular chains forming the polymer.Also disclosed is a process for making the polymer by high energy radiation of a normally solid, high molecular weight, linear, propylene polymer in a reduced active oxygen environment, maintaining the irradiated material in such environment for a specific period of time, and then deactivating free radicals in the material.Further disclosed is the use of the strain hardening polymer in extensional flow operations such as, for example, extrusion coating, film production, foaming and thermoforming.

Abstract: Disclosed is a polyolefin composition comprising (A) an irradiated, normally solid, high molecular weight, amorphous to predominantly crystalline olefin polymer material and (B) a non-irradiated propylene polymer material or a mixture thereof with an olefin copolymer rubber.The polyolefin composition of this invention also provides improved retention of embossing definition commonly referred to as grain retention, when the composition is extruded and embossed, with or without subsequently thermoforming.

Abstract: Polymer compositions having improved resistance to thermoforming sag are disclosed. The compositions comprise a first and second portion selected from the group comprising polypropylene, propylene-ethylene copolymers and mixtures thereof wherein a first portion of the composition is (1) mixed with from about 500 to about 3000 ppm of antioxidant; and (2) irradiated with a dosage of from about 10 to about 20 Mrads gamma or electron beam of ionizing radiation in air, and the second portion of said polymer composition is non-irradiated. The first portion is present in an amount effective, from about 1.0% to about 10.0%, to increase the elasticity of the polymer composition in the molten state by at least 10% as compared to the second portion of said polymer composition.

Abstract: Disclosed is a normally solid, high molecular weight, non-linear, substantially gel-free, propylene polymer material characterized by high melt strength due to strain hardening which is believed to be caused by free-end long chain branches of the molecular chains forming the polymer.Also disclosed is a process for making the polymer by high energy radiation of a normally solid, high molecular weight, linear, propylene polymer in a reduced active oxygen environment, maintaining the irradiated material in such environment for a specific period of time, and then deactivating free radicals in the material.Further disclosed is the use of the strain hardening polymer in extensional flow operations such as, for example, extrusion coating, film production, foaming and thermoforming.

Abstract: Disclosed is a propylene polymer composition consisting essentially of (A) a propylene polymer resin and (B) from 0.05 to 0.2 parts of a normally solid, high molecular weight, gel-free, propylene polymer material having (1) a branching index of less than 1 and significant strain hardening elongational viscosity, or (2) at least (a) either z-average molecular weight M.sub.z of at least 1.0.times.10.sup.6 or a ratio of the z-average molecular weight M.sub.z to weight average molecular weight M.sub.w, M.sub.z /M.sub.w, of at least 3.0 and (b) either equilibrium compliance J.sub.eo of at least 12.times.10.sup.-5 cm.sup.2 /dyne or recoverable shear strain per unit stress Sr/S of at least 5.times.10.sup.-5 cm.sup.2 /dyne at 1 sec.sup.-1.

Abstract: A lubricious polymeric composition which is stable toward sterilizing radiation includes a semicrystalline polyolefin of narrow molecular weight distribution having incorporated therein a liquid mobilizing additive, a radiation stabilizing amount of a hindered amine, a lubricating amount of an erucic acid derivative and a clarifying amount of a sorbitol derivative. The invention includes a sterilized article fabricated from the composition and a method to radiation sterilize the article.

Abstract: A radiation-resistant polypropylene resin composition is disclosed which comprises a polypropylene having a substantially syndiotactic structure, and if desired, a phosphorus-containing anti-oxidant, an amine-containing anti-oxidant and/or a nucleating agent. Molded articles obtained from this resin composition can be utilized as containers for foods and medicines, and their physical properties scarcely deteriorate during sterilization by radiation.

Abstract: A lubricious polymeric composition which is stable toward sterilizing radiation includes a semicrystalline polyolefin of narrow molecular weight distribution having incorporated therein a liquid mobilizing additive, a radiation stabilizing amount of a hindered amine, a lubricating amount of an erucic acid derivative and a clarifying amount of a sorbitol derivative. The invention includes a sterilized article fabricated from the composition and a method to radiation sterilize the article.

Abstract: Polymer compositions having a first and second portion selected from polypropylenes, polyethylenes, propylene-ethylene copolymers and mixtures thereof having enhanced crystallization properties and a method for producing the same are disclosed. Antioxidant is mixed with the first portion, 0.01 to 1.25 wt %, of the composition which is then irradiated to a dosage of 5-30 Mrads of ionizing radiation in air to induce cross linking. The irradiated first portion is then blended with the non-irradiated second portion. The cross-linked polymer is believed to provide nucleation sites for the initiation of crystallization, thereby enhancing crystallization of the polymer as evidenced by elevated DSC freeze points. Crystallization of the polyolefin is enhanced without any detrimental effects on hexane or xylene extractability of the polymer and without degrading the composition to any appreciable extent.

Abstract: Irradiated polypropylene articles of non-crystalline mesomorphous polypropylene and a method for preparing the articles are provided. The articles are irradiated with a sterilizing dosage of ionizing radiation. The irradiated articles such as films and blown microfiber webs are substantially undegraded after storage periods of as long as six months.

Abstract: A release material of a good release property is prepared by shaping a resin composition comprising a thermoplastic polyolefin resin, a dimethylpolysiloxane and a functional compound, irradiating the shaped composition with electron beams, and if desired, heat-treating the shaped composition.

Abstract: A method for increasing the intrinsic viscosity of polypropylene having a substantially syndiotactic structure is disclosed which comprises the step of irradiating the syndiotactic polypropylene with radiation in the absence of oxygen. After the irradiation, the polypropylene is preferably heated. Furthermore, the polypropylene having the substantially syndiotactic structure which remains in a melting state can be irradiated with radiation. The polypropylene having the substantially syndiotactic structure is preferably polypropylene in which any diffraction line is not substantially observed in a spacing of about 7.1 .ANG. by X-ray diffraction.

Abstract: A copolymer of trans-1,4-hexadiene and propylene, and a method for its preparation. The copolymer is isotactic, essentially free of cis-1,4-hexadiene, and contains from 0.01 to 5 mole percent 1,4-hexadiene. The copolymer is radiation-stabilized against molecular weight degradation, and cross-links to form gel upon exposure to radiation. The copolymer is prepared by contacting a mixture of propylene and 1,4-hexadiene essentially free of cis-1,4-hexadiene with a coordination catlyst, e.g. Ziegler-Natta catalyst, under copolymerization conditions. Hydrogen is used to moderate the molecular weight of the copolymer and enhance the catalyst activity.

Abstract: Disclosed is a method of treating a free-radical-containing, optionally room-temperature-aged, irradiated, normally solid high-molecular-weight, semi-crystalline propylene polymer material at about from 40.degree. C. to 110.degree. C. for at least about 10 minutes before being exposed to the higher temperatures that deactivate the residual free radicals therein. Treatment of the polymer at the intermediate temperature causes recombination, and better utilization, of free radicals with the production of more long-chain branching. A two-stage fluid bed process, with a first stage at the intermediate temperature for radical recombination and a second radical-deactivation stage at a higher temperature, is preferred.

Abstract: The composition of crystalline 1-butene polymer comprising(a) a crystalline 1-butene polymer containing a 1-butene component as a main component, and(b) a radical-treated crystalline olefinic polymer having (1) a boiling p-xylene-insoluble content of 30% by weight at most and (2) the relation satisfying the following expressionTc.sup.CL -Tc.sup.O .gtoreq.1wherein Tc.sup.CL is the crystallization temperature (.degree.C.) of the radical-treated crystalline olefinic polymer, and Tc.sup.O is the crystallization temperature of the crystalline olefinic polymer before the radical treatment, and (c) the proportion of the radical-treated crystalline olefinic polymer (b) being 0.2 to 100 parts by weight per 100 parts by weight of the crystalline 1-butene polymer (a).

Abstract: The composition of crystalline 1-butene polymer comprising:(a) a crystalline 1-butene polymer containing a 1-butene component as a main component, and(b) a radical-treated crystalline olefinic polymer having (1) a boiling p-xylene-insoluble content of 30% by weight at most and (2) the relation satisfying the following expressionTc.sup.CL -Tc.sup.O .gtoreq.1wherein Tc.sup.CL is the crystallization temperature (.degree.C.) of the radical-treated crystalline olefinic polymer, and Tc.sup.O is the crystallization temperature of the crystalline olefinic polymer before the radical treatment, and(c) the proportion of the radical-treated crystalline olefinic polymer (b) being 0.2 to 100 parts by weight per 100 parts by weight of the crystalline 1-butene polymer (a).

Abstract: The disclosed method provides an electret filter having a permanent electrostatic charge and formed of polymer fibers having an intrinsic viscosity of 1.5 or less. Fibers of the requisite viscosity are formed into a non-woven fabric and fed, at room temperature, through a gap between a discharge electrode and a ground electrode while being tightly pressed against the ground electrode. The ground electrode preferrably presents a polished metal surface for contact with the web.