5714results about "Melt spinning methods" patented technology

This invention relates to a process of melt blowing a cellulose solution through a concentric melt blown die with multiple rows of spinning nozzles to form cellulosic microfiber webs with different web structures. The process comprises the steps of (a) extruding a cellulose solution (dope) through a melt blown spinneret with multiple rows of spinning nozzles; (b) drawing each individual extrudate filament to fine fiber diameter by its own air jet; (c) coagulating and entangling the fine fibers with a series of pressured hydro needling jets of recycling solution of the mixture of cellulose solvent and non-solvent in the spin-line; (d) collecting the stream of microfibers, air and needling jets on a moving collecting surface to form cellulosic fiber web; (e) hydro-entangling the said pre-bonded web downstream with at least one set of hydro needling jets of recycling solvent/non-solvent solution for forming well bonded nonwoven web; (f) regenerating the fine fibers in at least one bath for at least 5 seconds; (g) further regenerating and washing the fine fibers in another bath for at least 5 seconds; (h) pinching the well bonded melt blown cellulosic nonwoven with pressure rollers to remove major portions of the non-solvent; (i) drying the nonwoven web by heat, or vacuum or both, and (j) winding the nonwoven web into rolls.

Nonwoven fibrous webs comprise fibers of uniform diameter that vary in morphology along their length. The variation provides longitudinal segments that exhibit distinctive softening characteristics during a bonding operation. Some segments soften under the conditions of the bonding operation and bond to other fibers of the web, and other segments are passive during the bonding operation. Webs as described can be formed by a method that comprises a) extruding filaments of fiber-forming material; b) directing the filaments through a processing chamber in which the filaments are subjected to longitudinal stress; c) subjecting the filaments to turbulent flow conditions after they exit the processing chamber; and d) collecting the processed filaments; the temperature of the filaments being controlled so that at least some of the filaments solidify while in the turbulent field.

A lyocell nonwoven fabric having fibers characterized by pebbled surfaces and variable cross sections and diameters along the fibers and from fiber to fiber, is disclosed. The lyocell nonwoven fabric is produced by centrifugal spinning, melt blowing or spunbonding. The lyocell nonwoven fabric has fibers that can be made in the microdenier range with average weights as low as one denier or less. The lyocell nonwoven fabric has fibers with low gloss, a reduced tendency to fibrillate and have enhanced dye receptivity.

The invention comprises polymer compositions containing 3-hydroxypropanoxy terminated polymer that exhibit reduced levels of degradation product emissions during processing, by contacting the polymer in the molten state with a melt stable, organic nitrogen-containing stabilizing compound, such as polyamide.

The invention relates to a method and a device for the production of essentially continuous fine threads made of meltable polymers. The polymer melt is spun from at least one spin hole (5) and the spun thread is attenuated using gas flows which are accelerated to achieve high speeds by means of a Laval nozzle (6). As a result of the specific geometry of the melt hole (4) and the position thereof in respect to the Laval nozzle (6), the temperature of the polymer melt, the throughout per spin hole and the pressures determining the velocity of the gas flow upstream and downstream from the Laval nozzle (6) are controlled in such a way that the thread reaches an internal hydrostatic pressure before solidifying, whereby said thread bursts into a plurality of fine threads.

The nozzle piece of the present invention is provided with circular cross sectional nozzles having different sizes disposed in a row in front of the die, with n-numbered smaller nozzles B (hole diameter: Db) between adjacent larger nozzles A (hole diameter: Da). It gives melt-blown non-woven fabric of monolithic structure in one step, composed of fine fibers having a diameter in a range from 1 to 10 mum diameter Variance ratio F of 2.0 or more and wide fiber diameter distribution.

A vascular prosthesis comprising a first layer having a predetermined first porosity and a second layer having a predetermined second porosity, wherein the first layer and the second layer are each made of first and second electrospun polymer fibers.

A method for electroblowing fibers is provided which involves the steps of: forcing a polymer fluid through a spinneret in a first direction towards a collector located a first distance from the spinneret, while simultaneously blowing a gas through an orifice that is substantially concentrically arranged around the spinneret, wherein the gas is blown substantially in the first direction; wherein an electrostatic differential is generated between the spinneret and the collector; and collecting the fibers, and its use in preparing submicron scale fibers of various types, particularly hyaluronan fibers, and the hyaluronan nanofibers thus formed.

The invention relates to a high-strength activated polyester industry yarn and a preparation method thereof. The high-strength activated polyester industry yarn is a modified polyester industry yarn of which the surface is coated with an activating agent and the high-strength activated polyester industry yarn is prepared from modified polyesters through spinning; the modified polyester is composed of polyester and aminoadipic acid gylcol ester, hydrogen-bond interaction exists between the aminoadipic acid gylcol ester and the molecular chains of the polyester, and the relative position of the aminoadipic acid gylcol ester and the molecular chains of the polyester is fixed; the free volume of the fiber is increased when the high-strength activated polyester industry yarn is at 70-80 DEG C, a part of activating agent molecules are dispersed into fiber gaps, more -OHs and -NHs with strong activity are introduced into the polyester molecules, a firm resinoid coating is formed on the surface of a polyester cord thread and the reactivity of the polyester fiber is improved; and the high-strength activated polyester industry yarn can be applied to triangular belt cords, radial tire cord fabrics and the like.

A method for forming biodegradable fibers is provided. The method includes blending polylactic acid with a polyepoxide modifier to form a thermoplastic composition, extruding the thermoplastic composition through a die, and thereafter passing the extruded composition through a die to form a fiber. Without intending to be limited by theory, it is believed that the polyepoxide modifier reacts with the polylactic acid and results in branching of its polymer backbone, thereby improving its melt strength and stability during fiber spinning without significantly reducing glass transition temperature. The reaction-induced branching can also increase molecular weight, which may lead to improved fiber ductility and the ability to better dissipate energy when subjected to an elongation force. To minimize premature reaction, the polylactic acid and polyepoxide modifier are first blended together at a relatively low temperature(s). Nevertheless, a relatively high shear rate may be employed during blending to induce chain scission of the polylactic acid backbone, thereby making more hydroxyl and/or carboxyl groups available for subsequent reaction with the polyepoxide modifier. Once blended, the temperature(s) employed during extrusion of the blended composition can be selected to both melt the composition and initiate a reaction of the polyepoxide modifier with hydroxyl and/or carboxyl groups of the polylactic acid. Through selective control over this method, the present inventors have discovered that the resulting fibers may exhibit good mechanical properties, both during and after melt spinning.

The subject matter disclosed herein relates generally to the production of a predetermined ratio of multicomponent fibers in combination with monocomponent fibers or other multicomponent fibers, preferably through a spunbonding process. After extrusion, these fibers can produce a fiber network that is subsequently bonded to produce a nonwoven fabric comprising multiple types of fibers. The multicomponent fibers within the network may be processed to remove one component by dissolution or to split the individual components into separate fibers. As a result, the fabric will be comprised of fibers with a range of diameters (micro- or nano-denier fibers as well as higher denier fibers) such that the fibers will not pack as tightly as in a homogeneous nonwoven fabric produced from one type of monocomponent or multicomponent fiber. The present invention additionally relates to methods for producing nonwoven fabrics with increased loft, breathability, strength, compressive properties, and filtration efficiency.

Fiber spinning of two polymer compositions wherein one of the compositions contains carbon nanotubes produces structures such as fibers, ribbons, yarns and films of carbon nanotubes. The polymers are removed and stabilization of the carbon nanotube material is achieved by post-spinning processes. The advances disclosed herein enable the carbon nanotube composites to be used in actuators, supercapacitors, friction materials and in devices for electrical energy harvesting.

A method of making regenerated cellulose microfibers includes forming segmented fibers with multiple longitudinally-extending segments of slightly different composition such that there is defined splittable interfaces between juxtaposed segments of the fibers which are then split into microfibers at yields of greater than 50%. Fibers so produced may be incorporated into absorbent sheet with other papermaking fibers to provide strength, softness, bulk and absorbency to tissue, towel, and personal care products.

This invention relates to nonwoven fabrics with advantageous characteristics and the method to produce these fabrics. Advantageously, the fabrics of the subject invention have increased thickness (loft) compared to conventional nonwoven fabrics and have high air permeability and open space while maintaining softness and strength at the same basis weight.

This invention discloses a fluorine-containing polymer and its application as ion exchange fiber material. The fluorine-containing polymer is a perfluoro resin containing sulfonylfluoride groups, and is shown in formula 1. The fluorine-containing polymer has ion exchange function, and is prepared by free radical copolymerization of perfluorosulfonyl vinyl ether, tetrafluoroethylene and hexafluoropropylene in the presence of dispersant, solvent and initiator. The dispersant/solvent is mixed solution of melamine derivative containing linear perfluoro hydrocarbon and water. The fluorine-containing polymer can be melt-spun into polymer fibers, which can be woven into fiber network that can be used as the reinforcing network material for ion exchange membranes and chlor-alkali ion membrane to reinforce and improve the ion exchange ability.

The invention relates a nylon 6 polymerization method and a direct spinning method of a melt of a polymer obtained with the nylon 6 polymerization method. A polyamide 6 prepolymer is prepared at the low temperature, the content of oligomers in the melt is controlled in advance, polymerization is completed before a large quantity of cyclic oligomers are generated with a condensation polymerization dynamic strengthening method, a nylon 6 polymer melt with certain molecular weight is acquired, the content of extracts in the product is smaller than or equal to 1.5 wt%, and the content of cyclic dipolymers is smaller than or equal to 0.2wt%; then, direct melt spinning forming is performed after condensation polymerization dynamic strengthening ends. The process is simple, energy consumption is further reduced while the utilization rate of caprolactam is increased, the obtained melt can be directly used for melt spinning, high-capacity large-scale production is easy to realize, a modifier can be added in the polymerization process, flexible production of nylon 6 is realized, and the nylon 6 can be applied to fibers for clothes, industrial filaments, engineering plastics and other fields.

Polymers that have extremely high melt viscosities are very difficult to extrude and stretch making it difficult to synthesize fibers of such polymers via conventional methods. A process is provided for producing a polymer fiber which involves blowing a mixture of a polymer and a gas through a nozzle such that polymer micro- and/or nano-fibers are produced. The polymer fibers are characterized in that they have a diameter less than the diameter of the outlet aperture of the nozzle.

Disclosed herein is a method for manufacturing a composite fiber filter having high efficiency and high functionality, the method comprising: melt-spinning microfiber yarns on a forming rod, which is made of a conductive material, grounded at one end thereof and rotatably driven, using a melt-spinning device, to form on the forming layer a microfiber layer consisting of the microfiber yarns; and electrospinning on the microfiber layer an electrospinnable polymer solution having a given dielectric constant, using an electrospinning device, so as to form on the microfiber layer a nanofiber layers consisting of nanofiber yarns, wherein the microfiber yarns of the microfiber layer and the nanofiber yarns of the nanofiber layer contain silver nanoparticles so as to have an antibacterial function.

Cellulose containing dope is extruded through orifices and into a stream of gas moving in a direction generally parallel to the direction that the filaments are formed with varying degrees of mechanical attenuation provided to the filaments using a take-up device, such as a winder.

A thermal bonding pattern for nonwoven fabric possessing improved abrasion resistance while retaining softness, comprising a basket-weave pattern or other pattern having a transition area (2) equal to at least 10% of bonding spot area (1) in FIG. 1, more preferably a transition area (2) equal to at least 50% of bonding spot area (1), and most preferably a transition area (2) equal to at least 100% of bonding spot area.

The invention described relates to a polyolefin blend composition suitable for spunbond fiber or filament compositions, and to fabric compositions and composite constructions therefrom, said blend comprising a) from 60-98 wt % of at least one random propylene copolymer having a comonomer content of from 8 to 25 wt % and a crystalline melting point (Tm) as determined by differential scanning calorimetry (DSC) of from about 40° C. to about 110° C.; and b) from 2-40 wt % of at least one substantially isotactic polypropylene homopolymer or copolymer comprising one or more C₂ and/or C₄-C₈ comonomer, having a crystalline melting point (Tm) as determined by DSC greater than or equal to 120° C. The blends of the present invention typically have a melt flow rate (MFR) of from 100 g/10min to about 500 g/10min.

The invention relates to a method of nanofibres production from a polymer solution using electrostatic spinning in an electric field created by a potential difference between a charged electrode and a counter electrode. The polymer solution (2) is for spinning supplied into the electric field using the surface of the rotating charged electrode (30), while on a part of the circumference of the charged electrode (30) near to the counter electrode (40) is a spinning surface created, by which is a high spinning capacity reached. Further the invention relates to a device for carrying out the method, where the charged electrode (30) is pivoted and by its (bottom) part of its circumference it is immersed in the polymer solution (2), while against the free part of the circumference of the charged electrode (30) is positioned the counter electrode (40).