# US 11,111,614 B2 · Method for tuning characteristics of a polyamide nanofiber nonwoven > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,111,614 B2 - Document ID: US11111614B2 - Status: Granted - Kind: B2 - Application number: 16/434,918 - Filed: 2019-06-07 - Published: 2019-12-12 - Granted: 2021-09-07 - Earliest claimed: 2018-06-08 - Assignees: Ascend Performance Materials Operations LLC - Applicants: Ascend Performance Materials Operations LLC - Inventors: Wai-Shing Yung; Chris Schwier; Albert Ortega; Scott E. Osborn - Web page: https://patentgrep.com/patent/US11111614B2 ## CPC - D04H 3/16: with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion - D01D 5/096: Humidity control, or oiling, of filaments, threads or the like, leaving the spinnerettes - D01F 6/60: from polyamides (from polyamino acids or polypeptides D01F6/68) - D04H 3/009: Condensation or reaction polymers - B29C 2948/92514: Pressure - B29C 2948/92704: Temperature - B29C 2948/92723: Content, e.g. percentage of humidity, volatiles, contaminants or degassing - D01D 5/0985: {by means of a flowing gas (e.g. melt-blowing)} - D10B 2331/02: polyamides (D10B2331/08 takes precedence) - D04H: MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL (weaving D03; knitting D04B; braiding D04C; net-making D04G; sewing D05B; tufting D05C; finishing non-woven fabrics D06); FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING {; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION}(non-woven fabrics having an intermediate or external layer of a different kind, e.g. of woven fabric, B32B) - D01D: MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS - D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS - B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) - D10B: INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES ## Abstract A method for tuning characteristics of a polyamide nanofiber nonwoven comprising the step of targeting a specific average nanofiber diameter and/or a specific relative viscosity for the polyamide nanofiber nonwoven. The specific average nanofiber diameter is within a range from 100 nm to 1000 nm and/or the specific relative viscosity is within a range from 5 to 75, e.g., from 15 to 50. The process further comprises the steps of extruding a polyamide composition having a moisture content with a pressurized gas through a fiber forming channel having a channel temperature to form the polyamide nanofiber nonwoven having the target average nanofiber diameter and/or relative viscosity and controlling the moisture content, the pressure of pressurized gas, and/or the channel temperature based on the specific average nanofiber diameter and/or the specific relative viscosity. ## Claims ### Claim 1 A method for tuning characteristics of a polyamide nanofiber nonwoven comprising the steps of: targeting a specific average nanofiber diameter and/or a specific relative viscosity for the polyamide nanofiber nonwoven, wherein the specific average nanofiber diameter is within a range from 100 nm to 1000 nm and/or the specific relative viscosity is within a range from 5 to 75; extruding a polyamide composition having a moisture content with a pressurized gas through a fiber forming channel having a channel temperature to form the polyamide nanofiber nonwoven having the target average nanofiber diameter and/or relative viscosity; and controlling the moisture content by drying the polyamide composition to have a moisture content of less than 0.02 wt. %, and rehydrating the dried polyamide composition. ### Claim 2 (depends on 1) The method of claim 1, wherein the specific average nanofiber diameter is within a range of 200 nm to 700 nm. ### Claim 3 (depends on 1) The method of claim 1, wherein the specific relative viscosity is within a range from 15 to 50. ### Claim 4 (depends on 1) The method of claim 1, wherein the moisture content is controlled from 0.005 wt. % to 1 wt. %. ### Claim 5 (depends on 1) The method of claim 1, wherein the pressure of the pressurized gas is controlled to range from 160 kPa to 220 kPa. ### Claim 6 (depends on 1) The method of claim 1, wherein the channel temperature is controlled to range from 270° C. to 330° C. ### Claim 7 (depends on 1) The method of claim 1, wherein the fiber forming channel comprises a die and/or a capillary. ### Claim 8 (depends on 1) The method of claim 1, wherein the polyamide nanofiber nonwoven is melt-blown and/or is free of solvent. ### Claim 9 (depends on 1) The method of claim 1, wherein the polyamide composition comprises a catalyst. ### Claim 10 A method for tuning the relative viscosity of a polyamide nanofiber nonwoven comprising the steps of: targeting a specific relative viscosity for the polyamide nanofiber nonwoven, wherein the specific relative viscosity is within a range from 5 to 75; extruding a polyamide composition having a moisture content to form the polyamide nanofiber nonwoven having the target relative viscosity; and controlling the moisture content based on the target relative viscosity. ### Claim 11 (depends on 10) The method of claim 10, wherein the relative viscosity is targeted to a targeted relative viscosity within the range from 15 to 50. ### Claim 12 (depends on 10) The method of claim 10, wherein the moisture content is controlled to range from 0.005 wt. % to 1 wt. %. ### Claim 13 (depends on 10) The method of claim 10, wherein the moisture content is controlled to range from 0.02 wt. % to 0.3 wt. %. ### Claim 14 (depends on 10) The method of claim 10, wherein the controlling comprises: drying the polyamide composition to have a moisture content of less than 0.02 wt. %; and rehydrating the dried polyamide composition. ### Claim 15 (depends on 10) The method of claim 10, wherein the polyamide composition is extruded through a fiber forming channel having a channel temperature and the channel temperature is controlled to range from 270° C. to 330° C. ### Claim 16 (depends on 10) The method of claim 10, wherein the polyamide nanofiber nonwoven is melt-blown and/or is free of solvent. ### Claim 17 (depends on 10) The method of claim 10, wherein the polyamide composition comprises a catalyst. ### Claim 18 (depends on 1) The method of claim 1, wherein the polyamide nanofiber nonwoven further comprises zinc oxide. ### Claim 19 (depends on 10) The method of claim 10, wherein the polyamide nanofiber nonwoven further comprises zinc oxide.